A Meta-Analysis of the Effect of Education on Social Capital

Transcription

1 A Meta-Analyss of the Effect of Educaton on Socal Captal Huang Jan ** "Scholar" Research Center for Educaton and Labor Market Department of Economcs, Unversty of Amsterdam and Tnbergen Insttute by Henrëtte Maassen van den Brnk "Scholar" Research Center for Educaton and Labor Market Department of Economcs, Unversty of Amsterdam Wm Groot Department of Health Scences, Maastrcht Unversty And "Scholar" Research Center for Educaton and Labor Market Department of Economcs, Unversty of Amsterdam ** Address: Huang Jan, Department of General Economcs, Unversty of Amsterdam, Room 11.04, Buldng E, Roetersstraat 11, 1018 WB Amsterdam, the Netherlands; Telephone number: ; E-mal: huang@tnbergen.nl. Henrëtte Maassen van den Brnk, Department of General Economcs, Unversty of Amsterdam, Room 11.05, Buldng E, Roetersstraat 11, 1018 WB Amsterdam, the Netherlands; Telephone number: ; E-mal: h.maassenvandenbrnk@uva.nl. Wm Groot, Department of Health Scences, Maastrcht Unversty, P.O. Box 616, 600 MD Maastrcht, The Netherlands; Telephone number: /177; Fax number: ; E-mal: w.groot@beoz.unmaas.nl. 1

2 Abstract To assess the emprcal estmates of the effect of educaton on socal trust and socal partcpaton - the basc dmensons of ndvdual socal captal a meta-analyss s appled, syntheszng 14 evaluatons on socal trust, and 68 evaluatons on socal partcpaton. The means of the study weghted populaton effect szes are for socal trust, and for socal partcpaton per year of schoolng (p-value<0.001) after correctng for publcaton bas. Therefore, one standard devaton of years of schoolng accounts for 1-17 percent of the standard devaton n socal trust and socal partcpaton. These results lend support to the argument that educaton plays a crucal role n the generaton of socal captal. Further analyss confrms the exstence of a relatve effect of educaton on socal partcpaton, and of a recprocal mechansm between the dmensons of socal captal. The analyss also suggests that the eroson of socal captal durng the past decades has concded wth a decrease of the margnal return to educaton. Fnally, we fnd dfferences n the return to educaton between US and other natons, and varatons for dfferent educaton attanments. Keywords: meta-analyss; educaton; ndvdual socal captal; socal trust; socal partcpaton; publcaton bas; JEL Classfcaton: I1, Z13 1. Introducton The nterest n socal captal has led to a profuson of studes on ts economc and socal effects, as well as ts sources of orgn and accumulaton mechansms. Socal captal as Putnam (1993, 1995, 000) connotes, s an aggregate concept that encompasses the assocaton networks, norms and trust that facltate collectve nteractons for mutual economc and socal benefts. The scope of socal captal ranges from the mcro and meso levels to the macro level (Grootaert, 1998; Grootaert and van Bastelaer, 001). The mcro level of socal captal, also called ndvdual socal captal, s generally seen as an aggregate of two dmensons - trust n general people and personal nvolvement n socal actvtes. The meso level refers to average level of trust, number and densty of socal groups n a gven communty. The macro level of socal captal ncludes the socal and

3 poltcal envronment that shapes socal structure and enables norms to develop. Putnam (1993) and Fukuyama (1995) also defne an ethnc level or cultural level to capture the heterogenety n the level of trust, norms of recprocty and conventonal habts n partcpatng n cvc actvtes across natons and races. In ths paper we focus on the effect of educaton on ndvdual socal captal. So far, the most compellng emprcal evdence n support of the socal captal theory comes from mcro level studes of socal captal. The mcro level of socal captal lends tself easer to a generalzaton of emprcal research than meso and macro level models. At the meso and macro level, there s no unform defnton for socal captal and no standard quanttatve economc measure of collectve socal captal avalable. In general, decsons to nvest n socal captal are made by ndvduals, not communtes. Wthout a unform defnton at an ndvdual level, t s dffcult to understand ts formaton (Glaeser, 001). It s commonly accepted that educaton s a central factor n the generaton of socal captal. There are many emprcal studes to corroborate ths perspectve. However, results sometmes vary across studes due to heterogeneous survey sources and model specfcatons. It s therefore of academc concern as well as of polcy value to evaluate the possble sources of the varatons n the estmated effect of educaton on socal captal n the lterature. Before proceedng wth the emprcal analyss, we hghlght the hypothetcal effect of educaton on socal captal. In the emprcal secton, we begn wth the evaluaton of the magntude of the global effect of educaton, by usng the fxed effects and random effects models. We wll extend the approprate model for further analyss on the nfluences of study characterstcs on the educaton effect. Senstvty tests - The Egger s test and Hedge s procedure - are appled to check and correct for publcaton selecton bas.. Causal Effect of Educaton on Socal captal and Research Questons Accordng to Putnam (1998), Glaeser and Sacerdote (1999), and Alesna and Ferrara (000), educaton s one of the most mportant determnants of socal captal. Educaton reflects an orentaton towards the future by strengthenng human captal and socal captal for economc and socal development. Schoolng spreads knowledge - the basc component of human captal, and cultvates socal norms - the core of socal captal. 3

4 Schoolng s the frst non-famlal context n an ndvdual s lfe where moral and cogntve capactes are traned (Offe and Fuchs, 00). Through cvl educaton from schoolng, students learn the basc norms and responsbltes n socety, as well as the functonng of democracy. Schools also provde forums and sponsor programs for communty actvtes where students can apply ther cvc knowledge to real world stuatons. Durng ther educaton, students practce n a peer culture that shapes values such as recprocty, respect and trust. Educaton also promotes socal coheson and strengthens ctzenshp when chldren of dfferent soco-economc backgrounds are enrolled n the same school system. Glaeser et al. (1999) assert that the most robust correlate of socal captal varables s years of schoolng: For example, the raw correlaton of years of educaton wth membershp n organzatons s 34 percent n the General Socal Survey (Glaeser et al., 1999). Usng the World Values Survey, they fnd a postve relatonshp between schoolng and membershp of organzatons n almost every country. Denny (004) fnds that acqurng a four year unversty degree s assocated wth a 10% hgher probablty of an ndvdual volunteerng. Putnam (1995, 000), Uslaner (1997, 1998), Alesna and Ferrara (000) also show that more educated people are more lkely to have hgher trust n other people and they tend to jon more socal organzatons and partcpate n socal engagements more frequently. Though educaton s not the only factor that determnes trust n general people and partcpaton n socal actvtes, t s a very powerful generator at the ndvdual level, even after controllng for health, ncome, age and gender (Ne et al., 1996; Putnam, 000). It s noteworthy that, accordng to Ne et al. (1996), one s socal captal can be affected not only by one s own educaton, but also by that of others around hm. Generally, the mpact of educaton on socal captal can be dstngushed nto a relatve effect and an absolute effect. The relatve effect ndcates that educaton s a proxy for relatve status, a sortng mechansm for people wth hgher ablty n acqurng socal captal. The absolute effect refers to the accumulaton of cvc values and knowledge. Gven that educaton merely serves to sort people of dfferent capabltes n socal captal, and does not add to cvc values and knowledge, t s not one s own educaton 4

5 level, but hs relatve educaton status n the regon (compared to the average educaton level n the regon or communty), that ndcates the level of ndvdual socal captal (Ne et al., 1996; Putnam and Hellwell, 1999). Therefore, f more people have a college degree, Ne et al. (1996) argue, perhaps the socologcal sgnfcance of the credental has been devalued. Ths perspectve offers a potental resoluton for the apparent paradox that socal partcpaton has not rsen (and by some accounts has even fallen) wth the ncrease n educatonal attanment. In ths paper we address several emprcal questons on the relaton between educaton and ndvdual socal captal. The man queston we address s: What are the effects of educaton on trust n general people and partcpaton n socal or cvc actvtes? We further provde some nterpretaton for the effects that we fnd. We also ask ourselves to what extent heterogenety between studes affects the return to educaton? For nstance, are gender dfferences a crtcal factor n explanng the varaton n the effects of educaton on socal captal? An ssue that has receved a lot of attenton s the perceved eroson of socal captal durng the past decades (Putnam 1995, 000). In ths paper we wll compare the margnal effect of educaton obtaned from surveys conducted durng the 1950s 1980s, wth that from surveys conducted after If Putnam (1995, 000) s correct, we may expect a declne n the margnal effect of schoolng years. Amercans are beleved to have more socal captal than people n other natons (Putnam 1995, 000). By means of a meta-analyss of the estmates taken from the surveys across natons, we are able to examne what role educaton plays n ths nequalty. As mentoned, a relatve effect on socal captal ndcates that educaton s a proxy for relatve status, whle the absolute effect refers to accumulaton of cvc values and knowledge. We wll assess both effects of educaton by evaluatng the effects of ndvdual schoolng years and average schoolng years n the regon. We further test whether the mpact of one more year of schoolng on trustng and partcpatng vares across dfferent levels of educaton, and whether t rses wth educaton attanments. 5

6 Coleman (1990) and Putnam (1993, 1995) suggest a recprocal effect between trust n general people and partcpaton n socal actvtes: Socal trust, norms of recprocty, networks of a cvc engagement and successful cooperaton are mutually renforcng (Putnam, 1993, p.180). Brehm and Rahn (1997) post an asymmetrc causal chan n whch trust s the drect outcome of cvc engagement. But ths asymmetrc assocaton s dsputed by Uslaner (1997), who argues that trust shapes cvc partcpaton. These hypotheses wll be tested by ncludng controls for recprocty between trustng and partcpatng n the meta-analyss. That the accumulaton of socal captal changes over the lfe-cycle s a commonly addressed theme n socal captal theory; we wll take t nto consderaton by studyng the mpact of educaton across dfferent lfe stages: early adulthood, mddle age and aged. 3. Meta-analyss Indcators, Effect sze and Smple Analyss 3.1 Indcators and measurements of the mcro level of socal captal As ndvdual socal captal s an aggregate of ndvdual trust n general people and personal nvolvement n socal actvtes, we consder the two dstnctve ndcators of ndvdual socal captal separately n our analyss. Socal Trust - the amount of trust ndvduals have n most people, those they know and those they do not know - s a common ndcator for trust n general people. Socal trust reflects the bond that people share across economc and ethnc groups (Rothsten and Uslaner, 004). Hgh levels of socal trust lead people to expect that others are cooperatve and not opportunstc n socal and economc exchanges. Socal trust also reduces transacton cost and helps solve the free-rder problem n provdng publc goods. Socal trust s usually measured by the response to the followng queston: Generally speakng, would you say that most people can be trusted or that you can t be too careful n dealng wth people? Ths operatonalsaton of socal trust has been wdely used n surveys around the world, ncludng the General Socal Survey (GSS) and the World Values Survey (WVS). Socal Partcpaton - an ndvdual s afflaton n groups or organzatons, and voluntary partcpaton n communty servces or actvtes organzed by socal groups - 6

7 s a general ndcator to denote the level of personal nvolvement n socal actvtes. Socal partcpaton covers all types of actve afflaton wth groups outsde the famly and voluntary actvtes unrelated to poltcal purposes, such as votng and lobbyng. A hgh level of socal partcpaton s supposed to rase cvc norms among people, ncrease the credblty of a government and fortfy the foundaton of a democratc socety, whch n the end mproves polcy outcomes (Smth 1999). Two sub-categores are dstngushed to capture the complexty and dversty of socal partcpaton: membershp n nonpoltcal groups (clubs and other organzatons) and partcpaton n voluntary actvtes 3. Actually, they are both measured as ether the possblty of jonng non-poltcal groups or partcpatng n voluntary actvtes, or the degree of socal nvolvement - number of membershps or frequency of partcpaton. 3. Effect sze and selecton crtera for meta-analyss A standard comparson, effect sze (ES), s necessary n the meta-analyss to evaluate the estmates across studes, between dmensons and wthn dmenson. The effect sze, n the smplest form, can be conceptualzed as a standardzed dfference between the treatment group and control group,.e. the rato of the dfference between the means to the pooled standard devaton (Glass, 1976). In ths meta-analyss, the effect sze s obtaned as the proporton of standard devaton n the dependent varable that one year of schoolng accounts for, by standardzng the study estmate wth the correspondng standard devaton. Two crtera were used for the ncluson of avalable lterature n the meta-analyss: (a) studes should focus on the determnants of at least one dmenson of socal captal at the ndvdual level wth formal educaton as a covarate n the model; (b) studes should have reported statstcal data (t-statstcs, p-value or standard error) that allow for estmaton by the fxed effects and random effects models. We created a dataset for our analyss that ncludes 57 studes. 6 studes provde estmates of the return to educaton on socal trust and 31 studes provde estmates on socal partcpaton. Table 1 presents some summary nformaton on the authors, year of publcaton (of the journal or the latest verson as a workng paper) and survey perod, 7

8 classfed by socal trust and socal partcpaton. All of the studes were publshed after The number of estmates vares markedly from 1 to 103. Most of the surveys used n the ndvdual studes refer to the 1990s. Informaton on demographc characterstcs are extracted from the studes and added to the data base. We also nclude ndcators for whether the ndvdual study has controlled for economc status (ncome and employment status), envronment (populaton densty, resdency length and development ndex), relgon, endogenety of the educaton varable, the relatve effect of educaton and recprocal mechansms wthn dmensons of socal captal. Table 1 Sources of Meta-analyss Study of Socal Trust No of ES Perod Study of Socal Partcpaton No of ES Perod Alesna & Ferrara<000> Alesna & Ferrara<000> 1990 Alesna & Ferrara<00> Brehm & Rahn<1997> Ana et al.<00> Carolyn Funk<1998> Andrew Legh<003> Cho<003> Brehm & Rahn<1997> Clabourn & Martn<000> Clabourn & Martn<000> Cutler & Hendrcks<000> Danel Lederman<005> Danel Lederman<005> Erc Uslaner<1998> Dhavan V. Shah<1998> Erc Uslaner<1997> DPasquale et al.<1999> Erc Uslaner<003> Elana La Ferrara<000> Erc Uslaner<004> Erc M. Uslaner<1998> Glaeser et al<1999> Glaeser et al<1999> Hellwell & Putnam<1999> Hellwell & Putnam<1999> Kenneth Newton<001> Kevn Denny<003> Klaus Levnsen<004> 3 00 Klaus Levnsen<004> 9 00 LEE et al.<003> Laura Tehen<000> Marschall & Stolle<004> L et al.<00a> Mllgan et al<003> Lu & Besser<003> Rahn et al.<003> 6 00 Marc Hooghe<003> Rothsten & Uslaner<004> Mllgan et al.<003> Rothsten<001> Kang & Kwak<003> 1997 Sacerdote & Glaeser<001> Patrca et al.<1999> Shah et al.<001> Patte et al.<00> Shah & Scheufele<000> Pppa Norrs<1996> Stenman et al.<005> Sacerdote & Glaeser<000> Wollebak & Selle<003> 1998 Sacerdote & Glaeser<001> Shah et al.<001> Soroka et al.<003> Thomas Sdee<003> Shah & Scheufele<000> 1997 Wellman et al.<001>

9 3.3 Basc statstcs and smple analyss for global effect In table we present the basc statstcs of the effect sze, the results of the fxed effects and random effects models, and test statstcs on the approprateness of the model. 14 estmates are collected from the studes on socal trust and 68 estmates from the studes on socal partcpaton As shown n panel A, the means of effect sze are for socal trust and for socal partcpaton. The results can be nterpreted as: One addtonal year of schoolng ncreases one s socal trust by 4.7 percent of ts standard devaton and ncreases socal partcpaton by 5.6 percent of ts standard devaton. In other words, one standard devaton of schoolng years ( years for most countres) accounts for the varaton n socal trust and socal partcpaton by 1-17 percent of ther standard devaton. For the studes that report probablty changes as the estmates, we can translate the mean effect sze as: one addtonal year of schoolng ncreases the probablty of trustng people by 0.04 and the probablty of partcpatng n assocatons and voluntary actvtes by Hence for people wth a 4-year unversty degree the probablty of trustng or partcpatng s at least 0.10 hgher than for hgh school leavers. Panel B of table presents the estmates of the pooled effect of educaton under the assumpton that the populaton effect sze s global across studes,.e. that study characterstcs have no mpact on the populaton effect sze. Both fxed effects and random effects models are performed to evaluate the global effect sze. The man dstncton between the two models s that the true effect sze (obtaned f the entre target populaton s evaluated) s allowed to be heterogeneous n the random effects model but not n the fxed effects model. It s shown that the estmates of the global effect sze vary for the fxed effects and random effects models, and the latter gves smlar estmates as the descrptve statstcs. The test statstcs (p-value < ) ndcate a strongly sgnfcant, postve return to educaton for both fxed effects and random effects models. The Q-statstcs n Panel C test the null hypothess that the true effect sze are homogenous across studes, and thus there s no resdual heterogenety n the global effect sze (between studes varance τ = 0). The Q-statstcs follow a Ch-squared dstrbuton wth N 1degrees of freedom, wth N beng the number of observatons n the meta-analyss. Sold evdence s found (p-value < ) for between studes 9

10 varance for both dmensons of socal captal, whch reject the null hypothess that the true effect sze s homogenous across studes. Therefore only the random-effects model s approprate for the evaluaton of the global effect sze. Resdual heterogenety wll always be consdered n the remanng analyss where we perform the extended model meta-analyss and the senstvty tests. Table Descrptve statstcs, estmates of global effect and test statstcs for fxed effect Socal Trust Socal Partcpaton A. Basc descrptve statstcs Mean s.d. Mean s.d. Effect sze Measure error (s. e of effect sze) N Socal Trust Socal Partcpaton B. Estmate of the global effect Estmate z-value Estmate z-value Fxed effects Random effects C. Test for fxed effects Socal Trust Socal Partcpaton Q-statstcs p-value < < Between studes varance τ Meta-analyss Extended Model and Senstvty Test 4.1 Analyss of extended model If there s no study feature affectng the effect sze, the estmates from table ndcate that the true effect sze of educaton s around for socal trust and for socal partcpaton. In our analyss of the return to educaton, the assumpton of a global effect does not seem realstc and tenable. In table 3 t s shown that the mean effect szes vary markedly for dfferent educatonal achevements, for survey perods before 1990 and after 1990, across dfferent stages of the lfecycle and between countres. We also notce that controllng for the average educaton level n the regon rases the effect sze substantally. 10

11 Table 3 Mean effect sze of educaton by characterstcs of the study and the populaton Socal Trust Socal Actvty obs mean std obs mean std Hgh School or above College graduate or above Mddle age people Aged people Survey before 90s Survey after 90s Ave Educ Contr No Ave Educ Contr US Survey Non US Survey In accordance wth the results of table 3 and the emprcal questons mentoned earler, some hypotheses are formulated how some of the study characterstcs mght nfluence the effect of schoolng on socal captal. A problem of the dataset s that we do not have much nformaton on specfc groups because few studes evaluated the educatonal return for partcular groups, such as at early adulthood, mddle age, aged, male or female, urban or rural, etc,. We therefore created an ndcator for the presence of nformaton on the target varables n the studes. The coeffcents of these group varables therefore represent the effect condtonal on a certan group beng observed. Table 4 presents the results of the extended model allowng for resdual heterogenety. We fnd a statstcally sgnfcant mpact of gender controls, envronmental controls and controls for recprocty for both socal trust and socal partcpaton. Controls for relgon, famly (famly sze or martal status), economc status and average educaton level n the regon, do not have a systematc effect on the two dmensons of socal captal. Economc status and average educaton controls only matter for socal partcpaton, whle famly and relgon controls only play a role n socal trust. Some study features have no statstcally sgnfcant nfluence on the returns to schoolng. These factors nclude modelng (OLS vs. Others), controls for endogenety (between educaton and socal captal) and meda nfluence (rado, TV and nternet). The nfluence of lteracy controls cannot be neglected. The lteracy controls reduce the effect of schoolng on socal partcpaton by a consderable degree. 11

12 The benchmark estmates of the overall average return to schoolng are for socal trust and for socal partcpaton. These benchmark rates show a declne for the perod after 1990, although ths declne s not statstcally sgnfcant for socal trust. Women seem to beneft less from educaton than men. The level of educatonal achevement s a key factor for the margnal return to schoolng. People wth at least a college degree receve a notably hgher return to educaton. Regonal dfferences have a small nfluence on the effect sze. The varable urban regons has an nsgnfcant, negatve mpact for both dmensons of socal captal. Ths ndcates that urban educaton may not be so effectve to promote ndvdual socal captal, compared to rural educaton. No systematc varaton s found for the stages across the lfecycle. Fnally, we emphasze the sgnfcant dstncton n the effects of educaton between the Unted States and other countres. Our fndng suggests that the hgher return to educaton s one reason why Amercan people tend to have more socal captal Table 4 Extended model for random effects meta-analyss Socal Trust Socal Partcpaton Coef. z Coef. z Gender control 0.0** *** 3.57 Famly control 0.01* Economc status control ** -.31 Model specfcaton (OLS=0) Endogenety control Recprocal mechansm control -0.01* *** Envronment control ** *** 3.4 Relgon control 0.018*** Meda control Average educaton control *** 3.64 Lteracy control *** Membershp ** 1.98 Female * Survey after 1990s ** -.1 College graduate or above ** *** 3.16 Urban regon Survey naton (US=0) *** *** Mddle age people Aged people * 1.91 Constant 0.064*** *** 3.46 τ N * Sgnfcant at 10% level. **Sgnfcant at 5% level. ***Sgnfcant at 1% level. 1

13 4. Publcaton bas, test and correcton It s crucal to understand that the results reported n prevous tables may be based because studes whch show some knd of sgnfcant effect are lkely to be publshed more frequently than those that fnd no sgnfcant effect, and because authors tend to neglect to report the test statstcs of nsgnfcant estmates. Ths problem, known as publcaton bas, arses n meta-analyss when the probablty that an estmate s observed s related to the statstcal sze of that estmate. Such selecton effects can lead to a substantal bas n the magntude of the effect sze (Hedges 199). Fgures are frst presented to provde a straghtforward llustraton of the correlaton between the effect sze and ts standard error. We wll also apply the Egger s test as a check for publcaton bas, and then employ Hedges correcton method to obtan a more accurate estmate of the effect sze. Scatter plots of the effect sze aganst ts standard error are presented n fgure 4, together wth the ftted value lnes. In the absence of any selectve reportng, the lne of the ftted values should be horzontal, as the return to schoolng should not vary n proporton to ts standard error. In fgure 1, however, the ftted value lne for socal trust s upward slopng whle t s downward for socal partcpaton, ndcatng the presence of publcaton bas for both dmensons of ndvdual socal captal..3 effectsze.. effectsze se se effectsze Ftted values effectsze Ftted values Socal Trust Socal Partcpaton Fgure 1 Scatter plot and ftted value lne of effect sze aganst ts standard error 13

14 To check for publcaton bas, Egger et al. (1997) suggest performng a regresson of the standardzed effect sze (dvded by ts standard error) aganst ts precson (.e. the nverse of effect sze s standard error) weghted by the recprocal of the varance of the estmate. If the ntercept dffers sgnfcantly from zero, ths may ndcate that publcaton bas s present. The statstcs of the Egger s test are presented n table 5. A sgnfcant bas s found for both socal trust and socal partcpaton. Hence the outcomes of the Egger s test strengthen our convcton about publcaton bas 7. Table 5 Egger s test st atstcs Socal Trust Socal Partcpaton Std. Effect sze Coef s.e t-value p> t Coef s.e t-value p> t Slope bas(ntercept) N * Note that the slope an d bas n the Egger s test s not the slope and ntercept of the ftted value lne. Hedges model of publcaton bas s based on the assumpton that there s a weght functon of p-values that determnes the probablty of a study beng observed. To solate the effect of p-values on the magntude of the effect szes and the estmates of the study characterstcs, the weght functon should be ntroduced nto the lkelhood. Detals of ths weght functon are outlned n Appendx as well as n the paper of Ashenfelter et al. (1999). In our analyss, the probablty of observaton of a study s specfed accordng to whether the p-value for that study s 0.01 < p < 0.05 denoted byω and p > 0.05 denoted byω 3, relatve to a default category of 0 < p < 0.01 denoted byω 1. The latter one s normalzed to unty. In the absence of reportng bas ω and ω should be equal to one as well. 3 We begn by estmatng the global effect model. Panel A n table 6 gves the results of the restrcted model where ω = ω3 and the random eff ects estmates. Panel B presents the results after correctng for 3 = 1. The global effect szes for socal trust and socal partcpaton are and respectvely, almost dentcal to the descrptve statstcs publcaton bas as we allow ω andω to vary. The global effect szes are moderately smaller for both dmensons. The lkelhood rato test, followng the Ch-squared statstcs 14

15 wth two degrees of freedom, ndcates that publcaton bas s a problem for the effect sze of socal partcpaton, but not for socal trust. Ths s not totally consstent wth the results from the scatter plots and the Egger s test, whch ndcate that publcaton bas matters for both dmensons of ndvdual socal captal. We wll relax the assumpton of a global effect n the next procedure and allow for the possblty that the effect szes vary by characterstcs of the studes. Table 6 Hedges model of global effect A. Restrcted ω ω 3 Socal Trust Socal Partcpaton Coef. z-value Coef. z-value Constant 0.046*** *** 5. 8 τ Log Lkelhood B.Unrestrcted Socal Trust Socal Partcpaton Coef. z-value Coef. z-value ω 1.43*** *** 4.6 ω *** *** 3. Constant 0.045*** *** τ Log Lkelhood Ch statstcs p-value 0.73 < N * Sgnfcant at 10% level. **Sgnfcant at 5% level. ***Sgnfcant at 1% level. Hedges model s extended by ntroducng the study characterstcs nto the lkelhood and the estmaton results are presented n table 7. We fnd clear evdence concernng publcaton bas for both socal trust and socal partcpaton. The Ch-squared test for the global effect also ndcates sgnfcant nfluences of study heterogenetes (p-value <0.0001). Ths result offers a clue why the global effect model does not provde consstent test statstcs for socal trust. The coeffcents for study characterstcs are very smlar to those n the extended model (see table 4) where we dd not correct for publcaton bas, except that the magntude chang es for several coeffcents. Nevertheless, ther sgns and levels of statstcal sgnfcance are generally dentcal. 15

16 Table 7 Test statstcs and estmates of extend ed Hedges model A. Statstcs for unrestrcted m odel Socal Trust Lkelhood value(restrcted) Lkelhood value(unrestrcted) Ch-statstcs for publcaton b as p-value 0.01 < Ch-statstcs for Global effect p-value < < B. Estmate of unrestrcted mo del Socal Trust Socal Partcpaton Socal Partcpaton Co ef. z-v alue Coef. z-value ω 0.86*** *** 4.30 ω *** *** 3.37 Gender control 0.04** *** 3.15 Famly control 0.013* Economc status control * Model specfcaton (OLS=0) Endogenety control * Recprocal mechansm control *** Envronment control *** *** 3.4 Relgon control 0.019*** Meda control Average educaton control *** 3.65 Lteracy control *** Membershp Female * Survey after 1990s * College graduate or above 0.01** *** 3.06 Urban regon Survey naton (US=0) -0.00*** *** Mddle age people Aged people * 1.66 Constant 0.079*** ***.56 τ N * Sgnfcant at 10% level. **Sgn fcant at 5% level. *** Sgnfcant at 1% level 5. Dscusson and concluson Ths meta-analyss confrms a sgnfcant, postve return to educaton on ndvdual socal captal. It ndcates that one standard devaton of years of schoolng accounts for the change n ndvdual socal captal by 1-17 percent of the standard d evaton n each dmenson. The results also suggest a hgher mpa ct of educaton on socal partcpaton than on socal trust. Trust n general pe ople, one s expectaton of other p eople behavor 16

17 regardng common socal norms, s a mental state that s more assocated wth personalty, such as optmsm (Uslaner, 1996), and personal experences such as socal backgrou nd, hstory of dvorce and beng cheated or robb ed (Uslaner, 1998 and Alesna and Ferrara, 00). Soc al partcpaton, especally the engagement n communty servce and other voluntary actvtes, s a type of behavor whch s less sub ject to ndvdual lfe experence, but more assocated wth socal s tructure and the level of cvc educaton. The hypothess that the effect szes are global s rejected by the Ch-squared test as shown n table 7. Gender dfference se ems to play a role n the mechansm by whch educaton stmulates socal captal. Controllng for gen der dfference s a sgnfcant covarate n the regresson on both dmensons of ndvdual socal captal. It s also found that wom en exhbt a negatve nfluence on the e ffect sze of socal partcp aton. There s no evdence that urban people receve a hgher return to educaton. The coeffcents for urban resdents are even negatve for socal trust and socal partcpaton, although not statstcally sgnfcant at the 10% level. Whle urban schools may have better access to resources, facltes and fnancng and may provde better qualty educaton than rural schools, the lfe experence n urban areas, whch are more heterogeneous and complcated, may spll over nto people s socal values (Uslaner, 1998 and Alesna and Ferrara, 00) and affect the mpact of schoolng on socal captal. For nstance, traumatc experences (volence, crmes) that one s more lkely to receve n urban areas may offset the postve effects of cvc educaton n school. If we compare the effect sze obtaned from surveys conducted before the 1990s wth that from the studes usng data for a later perod, we observe a declne n the effect of educaton on socal partcpaton. Ths s not the case for socal trust, although the estmate s also negatve n the extended models. The declne n the return to educaton provdes an explanaton for the eroson of socal captal (cvc engagement) n the Unted States (Putnam 1995, 000), despte a dramatc ncrease n educatonal attanment durng the last half century. It s noteworthy that our fndng s at odds wth the upward trend n the wage effect of schoolng, as found n a meta-analyss of wage return to educaton by Ashenfelter et al. (1999). One possble nterpretaton for ths dscrepancy s that there s a trade off between the return to educaton on human captal and that on socal captal. Wth ncreased globalzaton and through publc polcy measures, competton between 17

18 frms and competton between ndvduals have become more ntensve. Increased competton may put more emphass on the role of educaton as a source of human captal. The overemphass of the human captal aspect of educaton could be detrmental to the contrbuton of schoolng on cultvatng socal captal for collectve welfare. For nstance, the programs of cvc educaton, whch are not drectly assocated to the compettve power or ncome n the future, may have become less mportant n school programs or may appear less attractve to students who are anxous for an educaton that provdes opportuntes for a good job. The trade off between the returns to human captal and socal captal also helps explan why the nequalty n returns between urban and rural regons may only exst n the generaton of human captal. More ntense economc competton n urban socetes may force urban schools to focus on the development of human captal at the cost of cultvatng socal captal. Our analyss provdes proof for the vew that educaton has a hgher effect on socal captal n the Unted States than n the rest of the world. These results also support the argument made by Putnam that Amercans partcpate more n communty servces and voluntary actvtes than people n other countres (Putnam, 1995, 000 and Uslaner, 1997). Amercans are beleved to have a longer tradton n partcpatng and volunteerng: the Unted States has played a central role n systematc studes of the lnks between democracy and cvl socety.because Amerca has tradtonally been consdered unusually cvc (Putnam, 1995, p.65). Ths tradton reflects on educaton as Amercan schools are more actve n encouragng students nto runnng student offces, partcpatng n cvc engagement and jonng varous assocatons. People wth larger socal network, more trust n other people and who partcpate more n socal actvtes durng schoolng wll dsplay hgher level of socal captal n ther adulthood as well (Stolle and Hooghe, 004). The meltng pot theory can also help explan why Amercans tend to receve a hgher educatonal return on socal captal. The Unted States has accepted more mmgrants, from more places around the world, than any other naton. Encouragng tolerance of ethnc dversty and creatng core values of a common Amercan hertage are the man subjects of the socal educaton programs n Amercan publc schools: By exposng students to knowledge about ethnc dversty and the 18

19 contrbutons of varous groups to our developng Amercan cvlzaton, educators n the socal studes may change negatve ethnc group stereotypes, reduce ntolerance, and enhance cooperaton for the common good (Cohen, 1986). The strongly sgnfcant effect of controllng for average educaton n socal partcpaton confrms the exstence of a relatve effect. For socal trust, no evdence s found n support of a relatve effect. The descrptve statstcs n table 3 show that the mean effect sze for socal partcpaton s n studes that do not control for average educaton, and n those controllng for average educaton (both are statstcally sgnfcant at the level). Ths provdes evdence for both an absolute effect and a relatve effect. The relatve effect does not domnate the absolute effect of educaton, so the total effect on socal partcpaton s stll postve and substantal. It may be dffcult to nterpret why the effect sze s postvely assocated wth the ncluson of control varables for the average level of educaton. A smple lnear model s chosen to elucdate ths nsght, assumng educaton to be the only determnant of socal partcpaton ( SP ): SP = a * 1 edu1 + b*( edu avedu) where a represents the margnal absolute effect of years of ndvdual schoolng on socal partcpaton, b represents the margnal sgnalng effect or relatve effect (years of schoolng compared to the average years of schoolng n the regon). If educaton has a sgnalng effect as well as an absolute effect on ndvdual socal captal, we expect both a and b to be postve. In addton, years of schoolng are postvely assocated wth the average level of educaton n the regon where he or she lves. Mathematcally, ndvdual educaton level s ncluded nto the calculaton of average educaton level. Furthermore, hgher educated people are more nclned to lve n regons wth a hgher average educaton level, snce people have a preference for a homogenous regon wth smlar socal-economc status. More detals can be found n Alesna and Ferrara (000), who show that socal-economc heterogenety reduces trust and feelngs towards other people. In the restrcted model, the covarate of average educaton level of the regon s dropped: SP = c*edu 1 Then the negatve effect of average educaton level wll be absorbed by ndvdual schoolng years. Thus the estmate of the effect of ndvdual educaton, coeffcent c n the restrcted model, wll be smaller than that n the full model, whch equals a + b. 19

20 Ths explans why we observe a postve mpact of the control varable for average level of educaton on the magntude of the effect of ndvdual schoolng years. The sze of the educaton effect vares wth the level of educaton. Effect sz es are sgnfcantly hgher for people wth a college degree or above. It suggests that the popular one-factor OLS model, where t s assumed that educaton can always be aggregated nto a sngle measure, say years of schoolng, may not be a suffcent model to capture the effects of educaton on socal captal. It s possble that a college educaton s crucal to learn to respect and trust other people, cultvate cvc behavor to jon socal groups and partcpate n voluntary actvtes, and therefore the effect of educaton demonstrates a substantal leap for people wth college degree. Alternatvely, a college degree may sgnal the exstence of unobserved ablty - ndvdual personalty or other nherent psychologcal attrbutes - that postvely affect both educatonal achevement and the level of ndvdual socal captal. There s evdence to suggest that controllng for a recprocal effect between the two dmensons of ndvdual socal captal nfluences the effect sze of educatonal return. Ths outcome confrms the noton of a vrtuous crcle (Putnam, 1995) n the accumulaton of socal captal. If socal trust s ncluded as an explanatory varable n the socal partcpaton equaton, the estmate of the margnal effect of schoolng years wll be lower. The reverse s also true. The ntuton behnd ths s straghtforward: snce educaton has a sgnfcantly postve effect on both dmensons, and there s a mutual, postve effect between these dmensons, the drect effect of educaton on a dmenson (after controllng for recprocal effects) wll be lower than the total effect (wthout controllng for recprocal effects). The sgnfcant mpact of controllng for recprocal effect also provdes support for the central role of schoolng n the generaton of socal captal. It s noted that the magntude of the recprocal effect s smaller for socal trust than for socal partcpaton, and n the former controllng for recprocal effects does not have a statstcally sgnfcant effect n Hedges extended model (see table 7). One explanaton s that, although a vrtuous crcle exsts for partcpaton and trust (Putnam, 1995), socal trust exerts a stronger effect on socal partcpaton than the other way around. Hence, contrary to the fndngs from Brehm and Rahn (1997), trust may stand at 0

21 the begnnng of the chan leadng to cvc nvolvement and socal network, rather than at the end of t (Uslaner, 1997). We do not fnd any substantal dfference n the effect sze of socal trust across lfe stages. For socal partcpaton, however, we do fnd a somewhat postve coeffcent for aged people. It may ndcate a declnng trend n the educatonal return on socal partcpaton over tme. Control varables for meda, such as rado, televson and nternet, have hardly any mpact on the effect educaton on socal captal. There has been some controversy of the nfluence of meda (televson and nternet) on the change of socal captal. Putnam (000) blames televsons as the culprt for the declne of socal captal n the US. Our results ndcate that meda do not weaken the role of schoolng, one of the most mportant sources of socal captal. Some outcomes from the meta-analyss pose several topcs for future research. For example, t wll be nterestng to further explore whether there s a trade off between the return to educaton on human captal or ncome, and that on socal captal. One may also go further and nvestgate whether a college educaton s a key treatment for people to obtan more socal captal. More studes also need to be done to examne the effects of educaton for men and women and over the lfe cycle. Acknowledgements The authors are grateful to Hessel Oosterbeek for hs assstance and comments on prevous versons of ths artcle. Notes s chosen as a crtcal value because the framework of socal captal was establshed n the 1990s and scholar clamed a major declnng trend of socal captal n the 1990s and 000s compared to that n 50s-80s. We classfy educaton level of people by hgh school or above and college graduate or above because few studes provde specfc comparson between dfferent educaton levels. 3 We create an dummy varable for group membershp and partcpaton n the meta-regresson of socal actvtes to capture the attrbute dfference: Beng a member of a certan group does not mean that ndvdual wll partcpate n the actvtes related to the group and other volunteerng; 1

22 and vce versa, partcpatng n voluntary actvtes (related or not to groups) does not mean that the ndvdual s a member of any group. 4 The standard devaton of probablty to trust general people and partcpate n socal actvtes (1=yes, 0=no), s generally 0.5 n most studes. 5 The reference group for the varable College graduate or above s hgh school dplomat or above. 6 The reference group for stages of lfecycle s early adulthood. 7 The Begg s test also confrms the exstence of publcaton bas for both dmensons of socal captal. Appendx 1. Calculaton of the effect sze: Most effect szes were obtaned from the unstandardzed regresson estmate of the educaton coeffcent. For example, the margnal effect of a year of schoolng from unstandardzed OLS and bnary models (logt and probt) where the dependent varable s 0/1, was standardzed by the standard devaton of dependent varable to obtan the effect sze. Some studes only provded standardzed coeffcents for educaton. Those estmates represent not the effect sze, but the proporton that one standard devaton of educaton years has accounted for the standard devaton of the dependent varable. In ths case we dvded the standardzed coeffcent by the standard devaton of schoolng years to obtan the effect sze of margnal schoolng year. A small proporton of studes (less than 5% of the total number) merely ndcated whether the estmate of educatonal effect exceeded the 1 percent, 5 percent, or 10 percent levels of statstcal sgnfcance. In these studes, we mputed the p-value of the effect estmate on the bass of the reported statstcal sgnfcance level. If the level of statstcal sgnfcance was reported to exceed the 5 percent level but not the 1-percent level, the p-value equaled.03, the mdpont between.01 and.05. If the level of statstcal sgnfcance exceeded 1-percent, t was assumed that p-value equaled.005. If the level of statstcal sgnfcance exceeded 10 percent but not the 5 percent level, t was assumed that p-value =.075. We dd not nclude n the dataset the nsgnfcant estmates that do not have specfc test statstcs.. The codng for dummes of educaton attanments A large amount of studes ncluded educaton nto the regresson as a dummy varable (ndcator for hgh school degree or ndcator for college). Smple calculaton was performed to translate these estmates nto the effect of margnal years: we dvded the coeffcent for the hgh school

23 dummy varable by 4, for some college by 5, and for college graduate by 6 to obtan the equvalent effect sze for a year of schoolng. Ths codng does not cause the effect szes systematcally dfferent from those from OLS as the results n table 4 and table 7 provde evdence that model specfcaton (OLS vs. others, manly bnary models) has no mpact on the effect sze. Because those dummy varables mentoned above provde further nformaton on the educaton level of the respondents, we created two varables n the meta-analyss - hgh school or above and college graduate or above - to evaluate whether people wth hgher educaton obtan a hgher return to educaton. The hgh school or above dummy n the meta-analyss equaled 1 f we obtaned the effect szes from studes usng a bnary varable whether the respondents has a hgh school certfcate or not (people wth at least a hgh school dploma compared to those who do not fnsh hgh school). The college graduate or above dummy n meta-analyss equaled 1 f we obtaned the effect szes from studes usng a bnary varable ndcatng whether the respondents had a college degree or not (so we obtaned the effect szes of educaton from those wth at least college degree compared to those wthout). 3. Treatments of mssng values on specfc groups On specfc groups we do not have much nformaton because few studes evaluated the educatonal return for groups lke people wth a partcular educaton level, gender urban or rural, or people at partcular lfe stages. Rather than droppng studes wthout nformaton on these four varables, we used the followng procedures that enable us to retan them: a. we ncluded a full set of ndcators, ncludng educaton level, urban and rural, gender and lfecycles. For each of these group varables mentoned, the category mssng was ncluded as a separate ndcator varable, showng whether that study focuses on the effect of educaton for the specfc group. b. We nteracted each of the group varables mentoned n a, wth the category ndcators that the varable s non-mssng. The coeffcent reported n the tables for each of these group varables, s the coeffcent on the nteracton of the group varable (e.g. female) wth the ndcator that the group varable has non-mssng value. These coeffcents therefore represent the effect of the group varable condtonal on ts value beng observed. c. The ndcators for mssng values were ncluded n the Ch-squared test for the global effect; but ths ncluson does not have any mpact on the rejecton of global effect n the extended model, as the p-value s smaller than for both dmensons, when we exclude the category ndcators. 3

24 4. Fxed effects model, random effects model and Hedge s test for publcaton bas 4.1 Fxed effects model, random effects model Two types of statstcal models have been used n meta-analyss to solate the effects of heterogenety between studes that cause estmates to dffer across the lterature: the fxed effects model and the random effects model. In the fxed effects model, the true effect sze (obtaned f the entre target populaton s evaluated) s assumed to be homogeneous n the studes ncluded n the analyss: t = t + µ t * ~ N( t where t s the estmated effect sze and t * s the true effect sze; v s the varance of the measurement error µ due to estmaton on a sample smaller than the entre target populaton. *, v The random effects model allows for heterogenety n the populaton effect szes, usually by * assumng the true effects follow a normal dstrbuton wth a mean t and a varanceτ : t = t + µ t t * * ~ N( t * ~ N( t ), v ) *, τ ) In meta-analyss τ s commonly called between studes varance. Clearly, the fxed effects model, where τ = 0, s a specal case of the random effects model. Most study estmates, however, are produced for dfferent treatments and dfferent populaton groups, over dfferent tme perods, n dfferent locatons, and so forth. Therefore the true effect sze t may be subject to the characterstcs of studes. In general, a lnear model s consdered * suffcent to capture the effect of study characterstcs: t t * = x + ε = x + ε + µ where x are observed characterstcs of the studes that cause varatons n the true effect and s the vector of coeffcents of the varables. There s no resdual heterogenety n the fxed effects model, thus resdual ε = 0 dstrbuton wth a mean ze ro and a varanceτ.. In the random effects model, resdual ε follow a normal 4