PREDICTING CRIMINAL RECIDIVISM IN PAROLED QUEENSLAND PRISONERS: FINDINGS FROM A MULTINOMIAL ORDERED PROBIT MODEL

Transcription

1 PREDICTING CRIMINAL RECIDIVISM IN PAROLED QUEENSLAND PRISONERS: FINDINGS FROM A MULTINOMIAL ORDERED PROBIT MODEL ANDREW WORTHINGTON *, HELEN HIGGS AND GLYN EDWARDS ** School of Economcs and Fnance, Queensland Unversty of Technology A multnomal ordered probt model s used to predct post-release performance n a sample of Queensland prsoners released between January 1992 and December Post-release performance s defned n terms of the serousness of parole breaches and/or reoffences over the length of the parole perod or untl Aprl The paper examnes two ssues. Frst, t evaluates the statstcal sgnfcance of a number of custodal and socoeconomc varables on the lkelhood of a parole breach or reoffence. Factors analysed nclude famly composton, age, occupaton, ethncty, the number of events n custody, the number of prson volatons and the length of sentence of the most recent custodal epsode. Second, the study compares the role of these factors n determnng ether breaches of parole or the more serous outcome of readmttance through crmnal actvty. All other thngs beng equal, the elastcty of readmsson wth respect to the set of explanatory varables vares markedly accordng to whether readmsson s through a parole breach or through actual recdvst behavour. 1. INTRODUCTION In Australa, as n most developed countres, prson populatons are rapdly expandng. For nstance, n Queensland [Australa s thrd most populous state and, based on present trends, soon to have the hghest mprsonment rate of any State n Australa (CJC 1998: 1)] the number of court appearances resultng n mprsonment (ncludng fully or partly suspended sentences) rose from 46 to 50 percent between 1992/93 and 1996/97 (57 to 64 percent for personal offences and 38 to 41 percent for property offences). Ths ncrease n the mprsonment rate has resulted n a dramatc ncrease n the number of sentenced offenders actually admtted to prson wth admssons growng by 98 percent over ths perod and a further 17 percent n the twelve months to 31 March By March 1998 the Queensland prson system was at approxmately 132 percent of capacty. * ** Correspondence to: Dr Andrew Worthngton, School of Economcs and Fnance, Queensland Unversty of Technology, GPO Box 2434, Brsbane QLD Tel. (07) ; Fax. (07) ; emal. a.worthngton@qut.edu.au Glyn Edwards s a current canddate n the Department of Economcs, Unversty of Queensland doctoral program, and Andrew Worthngton s a recent graduate.

2 2 These fgures are nterestng n that mprsonment rates have generally not been matched by trends n the rate of offences across many categores of recorded crme n Queensland. For example, the overall rate of recorded offences aganst the person (ncludng serous assaults, robbery offences, murder, and reported and attempted rapes) has been bascally stable snce 1993/94, and the rate of recorded offences aganst property (break and enter, stealng, and motor vehcle offences) has ncreased only slghtly (CJC 1998: 2). The remanng broad category of recorded crme, namely other offences has contnued to ncrease, though t s argued that ths may reflect greater law enforcement actvty by polce, rather than an ncrease n offendng. Wthn ths category, the rate of recorded drug offences rose by 5.4 percent (largely possesson of drugs and/or tems for use n consumng drugs, wth cannabs typcally beng the drug sezed by polce), wth the rate of good order offences (resstng/hnderng polce, dsorderly conduct, and language offences) remanng stable. At the same tme, the Queensland mprsonment rate (excludng partly or fully suspended sentences) has also rsen despte a number of procedures amed at reducng the prson populaton. For example, the number of suspended sentences mposed has ether remaned stable or slghtly decreased, wth 1996/97 fgures suggestng that an addtonal 200 to 250 people are sent to prson by hgher courts through a declnng trend n the use of ths opton by the hgher courts. Lkewse, communty custody facltes (ncludng home detenton) are stll beng under-utlsed and parole has been ncreasngly dened beyond elgblty dates for communty release (CJC 1998: 13). For example, only 179 of the 220 avalable places n the communty custody program were flled as at 30 June Furthermore, from ths relatvely smaller set of paroled prsoners the number of offenders admtted to prson after revocaton of nterventon-type orders (ncludng home detenton, parole, and probaton) has contnued to grow and has added to the burgeonng prson populaton. For example, and as noted earler, appearances for other offences have prmarly accounted for the growth n the mprsonment rate, and of ths a major component has been enforcement of order appearances (ncludng breaches of home detenton, leave of absence, probaton or recognsance, and parole). Australa s ncreasng mprsonment rate, the growth of enforcement of order appearances and the declnng use of communty release touch on two mportant aspects of the economcs of prsons lterature [see, for example, Buchanan and Hartley (1992), DIulo (1996) and Avo (1998)]. Frst, servng tme n prson, as well as partcpatng n varous prson and postrelease programs, may have ether postve or negatve effects upon the actvtes of released prsoners (Avo 1998: 154). The obvous focus s the rate of crmnal recdvsm (a varously

3 3 defned measure relatng to the crmnal actvty of released nmates). Avo (1998: 154) argues that nalng down the specfcs of the relatonshps s clearly an mportant factor n evaluatng overall socal polces towards crme as well as n evaluatng specfc programs for ncarcerated and paroled offenders. Ths objectve s partcularly mportant n that prson overcrowdng has been recognsed by Queensland s Crmnal Justce Commsson (1998: 14) as a lkely contrbutor to an ncrease n the number of reported assaults by prsoners on other prsoners, along wth other matters relatng to an ncrease n the number of deaths n prson custody, and the fact that prsoners are generally spendng longer perods of tme n secure custody. Economc models of recdvst behavour whch examne these socal ssues are now relatvely commonplace, except n Australa [for exceptons see Broadhurst and Maller (1990) and Bodman and Maultby (1997)], and the emprcal analyses of ths economc approach to prsons proceeds apace [see, for nstance, Schmdt and Wtte (1989), Km (1993), Lattmore et al. (1995) and Benda and Tollett (1999)]. There s a need to quantfy the mpact of these custodal and tradtonal soco-economc characterstcs on crmnal recdvsm n Australa. Second, the dffculty of prsoners n obtanng release through strcter early release gudelnes, and the dramatc ncrease n the rate at whch such communty correcton orders are revoked, suggests an openng for the economc analyss of the parole functon n Australan prsons. In general, parole s argued to reduce socal costs by promptng prson nmates to behave and by decreasng the number of person-days of ncarceraton suppled. On the other hand, a system utlsng parole and/or probaton reduces the costs of crme to potental offenders and reduces the ncapactaton effect (Avo 1998: 145). An effcent punshment system would attempt to balance these costs and benefts and an emergng lterature exsts on the rate at whch released offenders return to crme whle on parole [see, for example, Mcel (1994) and Garoupa (1996; 1997)]. However, n contrast to the analyss of recdvsm n the strctest sense (where released prsoners are readmtted on the bass of a return to crmnal actvty) hypotheses lnkng the custodal and soco-economc characterstcs of parolees to readmttance through often relatvely mnor breaches of parole condtons are relatvely underdeveloped. Furthermore, there s an obvous need to nvestgate economc models of recdvsm wthn the context of a judcal system that reles heavly on parole, and to smultaneously address the mpact of parole orders on the lkelhood of a return to crmnal actvty.

4 4 Accordngly, the purpose of the present paper s to nvestgate the role of both custodal and soco-economc characterstcs n determnng the rate of recdvsm n paroled Australan prsoners. The paper tself s dvded nto four man parts. The frst secton outlnes the models for the analyss of recdvsm and readmttance to custody through parole volatons for Queensland prsoners. The second secton dscusses the custodal and soco-economc characterstcs thought to explan recdvst behavour. The results of the analyss are examned n the thrd secton. The paper ends wth some bref concludng remarks. 2. DATA AND MODEL ESTIMATION The data used n ths study s extracted from the Queensland Correctve Servces Commsson (QCSC) records of sx hundred and twenty nmates paroled between January 1992 and December The data s composed of three sets of nformaton. The frst set conssts of parolee soco-economc characterstcs (at tme of ncarceraton). Characterstcs recorded nclude ethnc background, age, number of chldren on admsson of custody, educatonal level, and employment and martal status. The second set of nformaton relates to parolee custodal characterstcs. Informaton collected ncludes the number of prevous custodal epsodes, years spent n custody and prsoner occupaton (f any) durng the current epsode, the number of separate prsons and prson volatons durng the current epsode, the securty level of the prson of release, and the parole perod served. The fnal set of nformaton relates to the post-release performance of paroled prsoners. The observaton perod n whch performance s assessed s ether the length of the parole perod or the length of tme from release untl Aprl Post-release performance (PRP) tself s defned n terms of the serousness of parole breaches and/or re-offences, f any, durng the observaton perod. Parolees are categorsed as ether (number of cases and percentage of sample n brackets): () nmates who have nether breached parole nor reoffended durng the observaton perod (PRP = 0) (360/58.06); () nmates who have volated or breached ther condtons of parole and been re-admtted to custody (PRP = 1) (183/29.52); and () nmates who have commtted another crmnal offence whle on parole and been re-admtted to custody (PRP = 2) (77/12.42). The analytcal technque employed n the present study s to specfy post-release performance as the dependent varable (y) n a regresson wth parolee soco-economc and custodal characterstcs as explanatory varables (x). Caulkns et al. (1996) and Benda (1999) also used varous groupngs of demographc, crmnal and psychologcal characterstcs to predct the

5 5 dchotomous outcomes of crmnal recdvsm. The nature of the dependent varable (postrelease performance) ndcates dscrete dependent varable technques are approprate. However, although the outcomes of the dependent varable are dscrete for each of the parolees, multnomal logt or probt models would fal to account for the ordnal nature of the dependent varable; that s, the severty of readmsson to custody, f at all. Ordnary regresson would err n the opposte drecton n that the dfferences between, say, PRP = 0 and PRP = 1 (no readmsson and parole volaton), would be treated n the same manner as that between, say, PRP = 1 and PRP = 2 (parole volaton and crmnal recdvsm), whereas n fact they are only a rankng. Accordngly, the followng multnomal ordered probt model wth smple heteroskedastcty s specfed: y * ε ~N[ 01, ], y = β = 0 f y = 1 f µ = 2 f µ... ' * x = J f y + ε, * 0 1 * µ < y * < y * µ 0, µ, µ. J 1 1 2, (1) Ths model comprses a form of censorng. The µs are unknown parameters to be estmated wth β and the unobserved random error term, ε, s assumed to be normally dstrbuted and standardsed to zero and one. The estmated coeffcents n the model provde nferences about the effects of the explanatory varables on the probablty of each post-release outcome such that: Prob ( y = 0) = Φ( β'x) Prob ( y = 1) = Φ( µ Prob ( y = 2) = Φ( µ... Prob ( y = 1 2 j) = 1 Φ( µ β'x) Φ( β'x) β'x) Φ( µ j - 1 β'x) 1 β'x) (2) where Φ(.) ndcates the standard normal dstrbuton. The estmated coeffcents are determned by maxmsng the jont probablty or lkelhood functon. 3. SPECIFICATION OF EXPLANATORY VARIABLES The frst set of explanatory varables used to predct parolee post-release performance relates to ndvdual soco-economc characterstcs. Selected descrptve statstcs (for quanttatve

6 6 varables only) are detaled n Table 1. The frst varable specfed s a qualtatve varable ndcatng whether the parolee s from an Aborgnal and Torres Strat Islander background (ABTS) (148 cases or percent of the sample). There s generally strong evdence to suggest that mnorty status s an mportant ngredent of post-release falure vs-à-vs readmttance to custody (Walker 1989; Mukherjee 1999; Benda and Tollett 1999). For example, Edwards (1998) used a table of rsk ndces to suggest that Aborgnes had a 78 percent greater lkelhood of re-offendng than parolees of other ethnc backgrounds. Smlarly, Sckles et al. (1979) and Schmdt and Wtte s (1989) studes of crmnal recdvsm n North Carolna found that non-whtes were more lkely to re-offend followng release. A postve sgn s hypothessed when post-release performance s regressed aganst ethnc background. The second soco-economc varable specfed s each parolee s age at tme of most recent ncarceraton (AGE). It s generally acknowledged that nmates n hgher age brackets are less lkely to re-offend or breach parole. For nstance, Schmdt and Wtte (1989) ncluded age as an explanatory varable n ther study. From ther estmated equatons, age was found to be the most sgnfcant varable. The ex ante sgn on AGE s negatve. The next two varables relate to addtonal soco-economc dmensons: namely, the number of years n educaton (EDU) and a qualtatve varable ndcatng employment status at tme of ncarceraton (EMP) (206 cases or percent of the sample). The a pror hypothess n both nstances s that better-educated nmates and/or those who possess current labour sklls have greater employment opportuntes and are less lkely to re-offend. Ths would mply a lower lkelhood of post-release falure and negatve ex ante coeffcents are hypothessed. The ncluson of these varables s a logcal extenson of Becker s (1968) costs and benefts of crmnal behavour to recdvst outcomes. More recent studes n ths area nclude Pehl and DIulo (1995) and Caulkns et al. (1996). The fnal two soco-economc varables specfed n the analyss relate to each parolees famly-based characterstcs. These are the number of chldren on admsson to custody (CHL) and the parolee s martal status (MRT) (ncludng de facto) (Sckles et al. 1979). To start wth, t s generally posted that those nmates who are n exstng martal relatonshps and/or have chldren tend to exhbt a lower rate of recdvsm than parolees who are sngle and wthout chldren. Both varables are therefore usually ncluded as proxy measures of domestc stablty and responsblty. The sgn on both coeffcents s thought to be postve.

7 7 An alternatve s that the need to provde fnancal support for famles may place addtonal pressure on parolees, though ths provder-role may be less mportant where welfare payments are avalable and the gap between ths and employment ncome s neglgble. No partcular a pror sgn s hypothessed when post-release performance s regressed aganst the number of chldren. Table 1 Selected contnuous varable descrptve statstcs Mean Standard devaton Frst quartle Second quartle Thrd quartle Fourth quartle AGE CHL EDU PRV SNT NOP VIO PAR The second set of explanatory varables used to dentfy post-release performance relates to each parolee s actual custodal characterstcs. The frst fve characterstc varables have postve relatonshps wth post-release performance. These are: () the number of prevous epsodes n custody (PRV); () the length of sentence of the most recent custodal epsode (SNT); () the number of prsons n whch ths custodal epsode was served (NOP); (v) the total number of prson volatons durng the current sentence (VIO); and (v) whether the prson of release was open or secure (medum or hgh securty) (SEC) (442 cases or percent of nmates were n medum-level securty or hgher). The basc hypothess for PRV, SNT, NOP, VIO and SEC s that nmates wth more prevous and more severe convctons, a greater propensty to commt volatons whlst n custody, and an unstable reform envronment as ndcated by frequent relocaton, are a hgh rsk group n terms of parole volaton and/or recdvsm. Doren (1998), for example, found that the number of prevous convctons was the most useful factor n determnng the true recdvst base rate for sex offences, and Dembo et al. (1995) lnked patterns of prevous arrest and custody wth potental vocatonal, lesure and famly problems wth smlar fndngs. Caulkns et al. (1996) also establshed that the number of prevous convctons n a number of categores, along wth a prsoner s custody classfcaton, was nstrumental n predctng recdvsm. Some addtonal explanaton may be found n the preparaton for release by lower securty

8 8 nsttutons and the fact that nmates n open custody have shown themselves to be more suted to re-ntegraton, havng ganed a lower securty level. Conversely, Brennan and Mednck (1994) n a study of recdvsm n a Dansh brth cohort found that rates of future arrest were negatvely related to the severty, frequency and varety of sanctons, though dscontnuaton of punshment generally resulted n recovery n crmnal arrests. Lastly, Lews (1986) argued that the general deterrent effect of longer sentences mght be dffcult to quantfy, especally gven the confoundng of the hypothessed deterrent and ncapactaton effects. One fnal qualfcaton s that t s unlkely that hgher rsk nmates (those wth longer sentences and/or securty classfcatons) would be granted parole. Ths would suggest that parolees usually possess a lower rsk profle (n terms of recdvsm) than the overall prson populaton. Regardless, and n common wth the large majorty of prevous studes, postve coeffcents are hypothessed when reoccurrence of crmnal actvty s regressed aganst measures of prevous crmnal actvty and severty. The fnal two custodal characterstcs ndcate whether an nmate was employed n servce and/or revenue-producng work whle n custody (OCC) (228 nmates or percent of the sample recorded a prson occupaton) and the parole sentence (n years) gven by the court (PAR). In the frst nstance, a number of studes have ndcated that prson work s an mportant contrbutor to crmnal reform (Leber and Mawhorr 1995). And n the second, Caulkns et al. (1996) and Edwards (1998), amongst others, have found that the lkelhood of crmnal recdvsm falls as the parole perod ncreases. One consderaton s that offenders must regularly report to a communty correctons offcer and may be requred to attend specfc programs or undergo drug testng durng the parole perod. The ex ante sgn on both OCC and PAR s thought to be negatve. 4. EMPIRICAL RESULTS The estmated coeffcents and standard errors of the parameters detaled above are presented n Table 2. Also ncluded n Table 2 are statstcs for jont hypothess and lkelhood rato tests, and the results of a predcton success table for the dependent varable. Four separate models are estmated. The estmated coeffcents and standard errors employng the entre vector of soco-economc and custodal characterstcs are shown n Table 1 columns 1 and 2. The results of estmatons usng frst, the set of soco-economc varables and then the set of

9 9 custodal characterstcs alone, are detaled n columns 3 and 4 and 5 and 6. All results are obtaned usng LIMDEP verson 7. The estmated models are hghly sgnfcant, wth lkelhood rato tests of the hypothess that all of the slope coeffcents are zero rejected at the.01 level usng the ch-square statstc. The percentage of observatons predcted correctly on the bass of the gven vector of socoeconomc varables vares from over 60 percent for the overall specfcaton (ncludng both custodal and soco-economc characterstcs), to just under 58 percent for the soco-economc characterstcs alone. The results also appear sensble n terms of both the precson of the estmates and the sgns on the coeffcents. In the full specfcaton, the estmated coeffcents for Aborgnal and Torres Strat Islander background (ABTS), martal status (MRT), the number of chldren (CHL), and the number of prsons (NOP) and prson volatons (VIO) durng the most recent custodal epsode are sgnfcant and conform wth a pror expectatons. These results are consstent wth the estmated coeffcents n the second regresson where only the set of soco-economc characterstcs are ncluded, though the coeffcent on AGE s sgnfcantly negatve. Ths would suggest that older parolees have a lesser lkelhood of readmttance to prson through ether parole volatons or further crmnal actvty. The sgn on educatonal level (EDU) s consstent wth a pror expectatons, though nsgnfcant, and prevous employment status (EMP) s nether sgnfcant nor consstent wth the hypothess of current labour market sklls reducng the lkelhood of recdvsm. Fnally, the model s reestmated wth only the set of custodal characterstcs. The estmated coeffcents and standard errors of ths regresson are detaled n columns 5 and 6 of Table 2. In addton to the levels of sgnfcance found n the orgnal specfcaton, the number of prevous epsodes n custody (PRV) s sgnfcant and postve ndcatng that a hstory of ncarceraton s assocated wth an ncreased lkelhood of recdvst behavour. Schmdt and Wtte (1984) lkewse found that the lkelhood of reconvcton s found to vary sgnfcantly wth the number of prevous convctons. However, the coeffcents on the length of sentence (SNT), the securty level of the prson of release (SEC), whether the prsoner had an occupaton (OCC) durng the most recent perod of custody, and the length of the parole perod (PAR) are not sgnfcant. Log-lkelhood tests are employed to reject the null hypotheses that the model of crmnal recdvsm could be estmated on the bass of the nested no custodal effect and no soco-economc effect models. We may therefore conclude that recdvsm and parole volaton are a functon of both custodal and socoeconomc characterstcs.

10 10 CONS. ABTS Table 2 Multnomal ordered probt model maxmum-lkelhood estmates Full Specfcaton No custodal effect No soco-economc effect Fnal specfcaton Coeffcent Std. error Coeffcent Std. error Coeffcent Std. error Coeffcent Std. error ** *** AGE ** *** *** ** *** *** EDU EMP MRT CHL ** * PRV ** * SNT NOP VIO *** *** ** * ** *** *** SEC *** *** OCC PAR µ(1) *** *** *** LnL LnL(0) LR *** *** *** *** *** S Astersks denote sgnfcance at the *.10, **.05, and ***.01 level; lnl log-lkelhood, lnl(0) restrcted slopes log-lkelhood, LR lkelhood rato statstc; values for µ(n) ndcate sgnfcance of cutoff parameter; sgnfcance of LR calculated usng χ 2 (p) where p = number of explanatory varables; S s the percentage of rght predctons. In order to further refne the overall specfcaton, Wald and LR tests were used to test combnatons of coeffcents for jont sgnfcance and on ths bass the varables for EMP, SNT and SEC were excluded from the fnal specfcaton [W = 0.87 χ 2 (3)]. Each of the remanng varables were tested n a smlar manner, though they faled to be excluded from the fnal specfcaton [W = ~ χ 2 (5)]. The refned model s presented n columns 7 and 8 of Table 2. The lkelhood rato for the refned model s compared wth the crtcal χ 2 value at the 5 percent level of sgnfcance and 10 degrees of freedom of At the 5 percent level of sgnfcance, the explanatory varables as a group can be used to nvestgate the postrelease performance of nmates from Queensland prsons. The most mportant determnants of post-release performance n terms of sgnfcance are the number of volatons n prson durng the current sentence (VIO), the number of prsons durng the current epsode (NOP), ethnc background (ABTS), martal status (MRT) and the number of chldren (CHL). The

11 11 results ndcate that there s a hgher probablty that nmates wth greater number of volatons and prsons durng ther current sentence or of Aborgnal ethnc background or wth large famles wll re-offend, whle marred nmates wll have a lower probablty of reoffendng. Ths result s consstent wth the model of Sckles (1979) where the explanatory varables an ndvdual wth a serous problem wth alcohol, martal status, mnorty status and age were most sgnfcant n explanng crmnal recdvsm. Schmdt (1989) and Caulkn (1996) also ncluded problems of alcohol or drug n ther analyses and these explanatory varables were found to be hghly sgnfcant. A lmtaton of ths model for the predcton of post-release performance of nmates n Queensland prsons s the lack of data on these socoeconomc factors. Table 3 Margnal effects for the multnomal ordered probt model Outcomes PRP = 0 PRP = 1 PRP = 2 ABTS AGE CHL EDU MRT PRV NOP VIO OCC PAR To facltate further comparablty, elastctes are calculated. These ndcate the margnal effects of each outcome on the probablty of post release performance (ranked from 0 to 2, wth 2 beng the worst offence). These are presented n Table 3. Usng these elastctes, t appears that ethnc background (ABTS), the number of chldren (CHL), the number of prsons durng current epsode (NOP) and the number of volatons n prson durng the current sentence (VIO) have the greatest postve mpact on the offence of volatng or breachng condtons of parole and re-admtted to custody (PRP = 1) wth a negatve mpact on the postrelease performance of nether breachng parole nor re-offendng durng the observaton perod (PRP = 0). Martal status (MRT) also has a greater mpact on reducng readmttance to custody through parole volatons (PRP = 1) than on readmttance through crmnal actvty (PRP = 2). Further, of all the varables examned, martal status has the greatest effect at the

12 12 margn n ndcatng parolees who have nether breached parole nor re-offended durng the observaton perod (PRP = 0). Lkewse, AGE, EDU, prson occupaton durng sentence (OCC) and the length of tme served on the parole perod (PAR) have the greatest negatve mpact on the offence of volatng or breachng condtons of parole and re-admttance to custody (PRP = 1) wth a postve mpact on the outcome of nether breachng parole nor reoffendng durng the observaton perod (PRP = 0). The number of prevous epsodes n custody (PRV) has a postve mpact on the offence of volatng or breachng condtons of parole and re-admtted to custody (PRP = 1) wth a negatve mpact on nmates who have nether breached parole nor re-offended durng the observaton perod (PRP = 0). A number of ponts can be made. Frst, t would appear that prmary nfluences on recdvsm through crmnal actvty and/or parole volatons nclude martal status and the number of chldren, the number of prsons resded n and the number of volatons commtted durng the most recent perod of custody, and background. Of these varables, the most sgnfcant margnal effects on a return to crmnal actvty occur where the parolee s from an Aborgnal and Torres Strat Islander background, the number of prsons held n the most recent epsode of custody, and the number of volatons commtted durng ths custody. Second, the nfluence of the custodal and soco-economc characterstcs of paroled prsoners vares across readmttance to custody through parole volatons and readmttance through a return to crmnal actvty. In fact, the margnal effect of all the custodal and soco-economc varables s hgher for readmttance to prson through parole volaton, than through further crmnal actvty. Fnally, the ablty of the model to accurately predct outcomes n paroled prsoners also vares across the measures of post-release performance. Whle the fnal specfcaton correctly predcted 93.6 percent of parolees as nether breachng parole nor reoffendng (at least n terms of court appearances), only 26.2 percent are predcted as ether parole volators or reoffenders, and slghtly less than 7 percent as recdvsts n the truest sense (notwthstandng the lmted observaton perod). Ths would suggest that models of crmnal recdvsm mght be more useful n dentfyng non-offenders and parole volators than the perpetrators of future crmnal acts. 5. CONCLUDING REMARKS The present study uses a multnomal ordered probt model to nvestgate the custodal and soco-economc determnants of crmnal recdvsm and parole volatons n 620 Queensland prsoners. The current paper extends emprcal work n ths area n at least two ways. Frst,

13 13 and as far as the authors are aware, t represents the frst attempt to apply qualtatve statstcal models of recdvsm n Australa. The evdence provded suggests that recdvsm s a functon (at least n the context of models of ths type) of Aborgnal background, martal and famly status, and the number of prsons held n and the number of volatons commtted n the most recent epsode of custody. Second, the study analyses n detal the varyng nfluences of custodal and soco-economc characterstcs. The results ndcate that custodal characterstcs, whlst n themselves useful ndcators of post-release performance, may be supplemented by soco-economc factors. Further, the nfluence of these factors vares across the dfferent measures of post-release performance, whether defned n terms of parole volatons the more serous outcome of a return to crmnal actvty. Unfortunately, from a polcy perspectve the results do more to dentfy lkely reoffenders, than to present possble ways to reduce the crmnal actvty of paroled prsoners (prson ndustry programs, longer parole perods, less frequent relocaton of prsoners, etc.). Of course, the study has ts lmtatons, all of whch suggest drectons for future research. To start wth, and followng Avo (1998: 156), one can conclude that there s value n usng sophstcated models n predctng recdvsm for random samples of released offenders, but that the models are not yet suffcently refned for applcaton to ndvduals. Put dfferently, whle the results of the study are suggestve of polcy changes, they are not suffcently developed to provde an emprcally feasble gude to parole boards, let alone Avo s (1998) selectve ncapactaton (where predctons of future behavour of ndvdual convcted offenders are used to set sentences and parole perods). Ths s partcularly relevant n that Mcel s (1994) effcent punshment system typcally requres a perod of punshment followed by supervsed release, and ths socally optmal punshment system s often demonstrated to vary across ndvduals. Whle some promsng advances have been made n the use of neural network models to predct crmnal recdvsm n ths regard, these have not yet been shown to exhbt any advantage over well-known statstcal methods (Caulkns et al. 1996). Nevertheless, the multnomal ordered probt model fndngs are sgnfcant and thereby provde the bass for a decson-makng framework for socal workers, psychologsts, psychatrsts and others who submt advce on ndvdual prsoners to parole boards. A second suggeston s that studes of recdvsm need to ncorporate more fully the economc model of crme. For example, gven that post-release performance n the present study s defned very broadly, much more needs to be done n examnng the serousness and type of crmnal actvty, the degree of certanty and severty of punshment for these crmes, and the

14 14 legtmate and llegtmate opportuntes avalable to paroled prsoners. Ths would more closely adhere to Becker s (1968: 176) semnal argument that a person commts an offence f the expected utlty to hm exceeds the utlty he could get by usng hs tme and other resources at other actvtes. Further, t s also lkely that the explanatory varables for recdvst outcomes are lkely to vary across tme; that s, n terms of post-release survval tme (the length of tme from release to recdvsm). It s argued that not only s ths varable of nterest n tself, but gnorng nformaton on length of tme to recdvsm (however defned) s statcally neffcent (Avo 1998: 155). Fnally, there s the persstent problem of smultanety n studes of crmnal recdvsm. That s, there s reason to beleve that an ndvdual s decson to engage n crmnal actvty can affect at least some of the more frequently specfed explanatory varables. For example, Sckles et al. (1979) provde an early smultaneous analyss of parolee s wages rates and the sentence tme (as a proxy for the severty of the offence). It s also lkely that exogenety s lkely to be questoned for other varables such as martal status, the number of chldren, employment and educaton. However, ths problem may not be as severe as ntally thought, at least n part. For example, Sckles et al. (1979: 171) found that the relatonshp between the crmnal actvty level and legtmate opportuntes may be recursve (legtmate opportunty affects the level of crmnal actvty, but not the reverse), rather than smultaneous. Nonetheless, the problem of accurately measurng the set of explanatory varables and then specfyng these varables n an approprate model presents an ongong challenge. REFERENCES Avo, K.L. (1998) The economcs of prsons, European Journal of Law and Economcs, 6(2), Becker, G.S. (1968) Crme and punshment: An economc approach, Journal of Poltcal Economy, 76(2), Benda, B.B. and Tollett C.L. (1999) A study of recdvsm of serous and persstent offenders among adolescents, Journal of Crmnal Justce, 27(2), Bodman, P. and Maultby, C. (1997) 'Crme, punshment and deterrence n Australa: A further emprcal nvestgaton, Internatonal Journal of Socal Economcs, 24, Brennan, P.A. and Mednck, S.A. (1994) Learnng theory approach to the deterrence of crmnal recdvsm, Journal of Abnormal Psychology, 103(3),

15 15 Broadhurst, R. and Maller, R. (1990) The recdvsm of prsoners released for the frst tme: Reconsderng the effectveness problem, Australa-New Zealand Journal of Crmnology, 23(1), Buchanan, C. and Hartley, P.R. (1992) Crmnal Choce: The Economc Theory of Crme and ts Implcatons for Crme Control, Centre for Independent Studes, Sydney. Caulkns, J., Cohen J., Gorr W. and We J. (1996) Predctng crmnal recdvsm: a comparson of neutral networks wth statstcal methods, Journal of Crmnal Justce, 24(3), Crmnal Justce Commsson (1998) Crmnal Justce System Montor, Aprl 1998, Vol. 3, Crmnal Justce Commsson, Brsbane. Dembo, R., Turner, G., Sue, C.C., Schmedler, J., Borderne, P., and Mannng, D. (1995) Predctors of recdvsm to a juvenle assessment center, Internatonal Journal of the Addtons, 30(11), DIulo, J.J. (1996) Help wanted: Economsts, crme and publc polcy, Journal of Economc Perspectves, 10(1), Doren, D.M. (1998) Recdvsm base rates, predctons of sex offender recdvsm, and the sexual predator commtment law, Behavoural Scences and the Law, 16(1), Edwards, G. (1998) Readmsson Rates among Inmates Released from Queensland Prsons: Identfyng Hgh Rsk Groups. Paper presented to the Economcs, Fnance and Internatonal Compettveness (EFIC) Semnar Seres, Queensland Unversty of Technology. Garoupa, N. (1996) Prson, parole and the Crmnal Justce Act 1991, Research n Law and Economcs 18. Garoupa, N. (1997) The theory of optmal law enforcement, Journal of Economc Surveys 11, Km, I-J. (1993) An economc analyss of recdvsm among drug offenders, Southern Economc Journal, 60(1), Lattmore, K. Vsher, C. and Lnster, R. (1995) Predctng rearrest for volence among serous youthful offenders, Journal of Research n Crme and Delnquency, 32(1), Leber, M.J. and Mawhorr, T.L. (1995) Evaluatng the use of socal sklls tranng and employment wth delnquent youth, Journal of Crmnal Justce, 23(2), Lews, D.E. (1986) The general deterrent effect of longer sentences, Brtsh Journal of Crmnology, 26(1), Mcel, T.J. (1994) Prson and parole: Mnmsng the cost of non-monetary sanctons as deterrents, Research n Law and Economcs 61, Mukherjee, S. (1999) Ethncty and crme Australan Insttute of Crmnology: Trends and Issues n Crme and Crmnal Justce, No. 117.

16 16 Pehl, A.M. and DIulo J.J. (1995) Does prson pay? Revsted, Bookngs Revew, 13(1), Schmdt, P. and Wtte A.D. (1989) Predctng crmnal recdvsm usng splt populaton survval tme data, Journal of Econometrcs, 40(1), Sckles, R.C. Schmdt P. and Wtte A.D. (1979) An applcaton of the smultaneous Tobt model: A study of the determnants of crmnal recdvsm, Journal of Economcs and Busness, 31(3) Weatherburn, D. (1992) Economc adversty and crme, Australan Insttute of Crmnology: Trends and Issues n Crme and Crmnal Justce, No. 40. Weatherburn, D. and Lnd, B. (1985) Poverty, parentng, peers and crme-prone neghbourhoods, Australan Insttute of Crmnology: Trends and Issues n Crme and Crmnal Justce, No. 85.