Police use of forensic science

Transcription

1 Police Research Group Police Research Series Paper 19 Police use of forensic science Helen McCulloch

2 Police Research Series Paper 19 Police use of forensic science Helen McCulloch Editor: Dr G. Laycock Home Office Police Research Group 50 Queen Anne s Gate London SW1H 9AT

3 Crown Copyright 1996 First Published 1996 Police Research Group: Police Research Series The Home Office Police Research Group (PRG) was formed in 1992 to carry out and manage research in the social and management sciences relevant to the work of the police service. The terms of reference for the Group include the requirement to identify and disseminate good policing practice. The aim of the Police Research Series is to present results of externally funded studies, and those carried out by the Police Research Group, in a way that will inform policy and practice throughout the police service. ISBN (ii)

4 Foreword Police use of forensic science support has been looked at by several studies over the last decade. This report examines the data routinely collected by forces themselves to provide a national picture on how forensic science was used in the calendar year The report reveals wide variation in the use of forensic science between forces, indicating the scope for using these data to identify and disseminate good practice on a more systematic basis. The report concludes that the routine assembly and analysis of the performance data collected by forces on a national basis is not currently feasible, but identifies the action needed to enable this to be done. S W BOYS SMITH Director of Police Policy Home Office, April 1996 (iii)

5 Acknowledgements I would like to thank all those who assisted in conducting this research. Particular thanks are due to: Professor Tilley for advice on both the research and the final report; the Scientific Support managers at the 11 sample forces and Dorset and Suffolk Constabulary for providing the data; and Amanda Walker at the Police Research Group for the many hours spent manually sorting and cleaning the data. HELEN MCCULLOCH 1995 The Author Helen McCulloch is a member of the Home Office Police Research Group. PRG would like to thank Dr Martin Stephenson, Scientific Support Manager at Merseyside Police, for acting as independent assessor for this report. (iv)

6 Executive Summary Since 1987 several reports have made recommendations for the collection of statistics on forensic support. Most forces now follow the PRSU recommendations (1991) and collect a broadly similar range of statistics. This report shows data, for the calendar year 1994, on the use of forensic support in 11 forces in England and Wales. The information was recorded on a standard computer software system (the Scenes of Crime Information Management System, SOCIMS) in each force and was collated by a special programme written by the system s producers. Despite all the forces using the same software, the data were recorded in many different ways, and a substantial cleaning and sorting process was needed. Although there was a fair amount of missing data, the two databases which resulted from this process provided a wealth of information on how forensic science was used, its costs and, to some extent, its usefulness. The two databases are described by a series of tables and, where possible, some accompanying analysis. It has been frequently recommended (Touche Ross 1987, Audit Commission 1990, PRSU 1991) that national statistics on the use of forensic science support should be centrally collected. During the data collection and analysis phases of this report, there was a high level of interest in the data, indicating a strong support for the collection of national statistics. Forces were particularly keen to compare their performance with other forces and to look for innovative uses of forensic support. Properly collected, national data could also be used to look for examples of good practice. However, collating the data from SOCIMS took almost a year and so obviously this would not be a feasible method for regular data collection Should it be decided that national statistics on the use of forensic support should be collected, it is recommended that: a central body should be tasked with producing standardised offence and test categories and more definitive definitions for evaluation scores. The PRSU recommendations should form the basis of these categories and definitions; the same body should be responsible for deciding what information is collected AND the collection, analysis and dissemination of the data; for the present collecting information should be a manual process, not electronic; and inter-force comparisons should be made as selectively and cautiously as possible. (v)

7 Contents Page Foreword Acknowledgements Executive Summary List of tables List of figures (iii) (iv) (v) (viii) (viii) 1. Introduction 1 Touche Ross and the Audit Commission recommendations 1 PRSU recommendations 1 The Scenes of Crime Information Management System (SOCIMS) 2 2. Methodology 4 The data used in this report 4 Missing data 6 3. General findings from SOCIMS Submissions 8 Tests 11 Costs Agencies providing forensic support 20 Market share for forensic providers 20 Variations between agencies and laboratories Drugs 23 Submissions and tests data 23 Costs The value of forensic tests 26 What the evaluation scores mean 26 Poor returns from the officers in the case 26 Basic data on evaluations 26 Evaluation by offence category and test type 29 Differences between forces in evaluations 31 Effect of turnaround time and other factors 32 (vi)

8 7 Forces which don t use SOCIMS 33 Suffolk Constabulary 33 Dorset Constabulary 33 8 Conclusions and recommendations 35 Appendices Appendix A Notified offences and submission rates by force 37 Appendix B Test type by offence type 38 References 39 Page (vii)

9 List of Tables Table No. Caption Page Table 1 Submissions by offence category 8 Table 2 Notified offences and submissions by force 9 Table 3 Differences in submission rates by force 10 Table 4 Number of items sent and tested per submission by offence type 12 Table 5 Submissions per case for murder/suspicious death offences 13 Table 6 Number of tests performed by test type 14 Table 7 Proportion of each test type accounted for by each of the four offence categories 16 Table 8 Costs and budgets for forensic support by force 18 Table 9 Cost of forensic support by offence 19 Table 10 Submissions and costs by forensic support provider 20 Table 11 Usage, costs and time taken for the most common tests by forensic provider 21 Table 12 Time taken by FSS laboratory 22 Table 13 Submissions and tests by forces notified drugs offences 23 Table 14 Cost of drugs testing 25 Table 15 Cross tabulation of SSU and OIC evaluation scores 27 Table 16 OIC evaluation by offence category 29 Table 17 SSU evaluation by test 30 Table 18 Range of evaluation scores across forces 31 List of figures Figure 1 Number of submissions per case for murders and suspicious deaths 12 Figure 2a SSU evaluation scores 27 Figure 2b OIC evaluation scores 28 (viii)

10 INTRODUCTION 1. Introduction This study forms a part of phase 2 of PRG s Police Operations Against Crime programme and was initiated to assist related work being undertaken by a National Project Team, jointly managed by ACPO and the FSS. Under the auspice of the National Project Team, a series of research projects were conducted which aimed to identify the most effective and efficient ways of using forensic science support. This report shows how forensic science was used nationally in 1994 by analysing data kept by the Scientific Support Units in a sample of 11 forces. Using the experience of collecting and collating these data, it then makes recommendations on the regular collection of national statistics. Touche Ross and the Audit Commission recommendations As part of their review of scientific support for the police, volume III of the Touche Ross report (1987) made references to the divergent way in which statistics were collected on the role of forensic support. In 1990, the Audit Commission (paper 8) produced more concrete recommendations for performance monitoring of scientific support. These fell into five main areas: forces should provide annual statistics on scene examination, fingerprints, forensic science and photography; a central body should collect and disseminate this information; the central body should develop an analytical framework so that ratios could be produced to compare performance between forces; comparisons between forces should be based on the Inspectorate s families of forces system; and the central body should also produce force reports that could be used as management information by force Chief Officers. Of the five recommendations, only the first has been adopted. This report concentrates on the collection and interpretation of statistics regarding forensic science support. PRSU recommendations From these recommendations, the Police Requirements Support Unit (PRSU 1991) produced more specific guidelines on how this process could operate. These were very detailed, but many are worth re-iterating here for two reasons. First, because the guidelines were followed very closely and so are a good starting point for understanding how such information is now collected, and second because several 1

11 INTRODUCTION definitions were set down, which are used both in the scientific support units and in this report. The main guidelines are discussed below. All submissions (any case submitted in whole or in part to any agency) should be monitored by crime category (termed offence category in this report) and sample type (termed test type in this report). The usefulness of the forensic submission to the case should be measured by the officer in the case (OIC) and the scientific support manager (SSM), these data are termed evaluation scores in this report. The PRSU recommended scale is: 1 Very useful 2 Useful 3 Limited use 4 No value PRSU also recommended that the SSM should evaluate the scientific value of each test. This is not now carried out in all forces. A scale of evaluation scores was suggested: 1+ Conclusive evidence which identifies suspect 1 Conclusive evidence which eliminates suspect 2 Strong evidence which identifies or eliminates suspect 3 Some evidence which identifies or eliminates suspect 4 No evidential value. The 1 score was rapidly discontinued in many forces, with 1 representing conclusive evidence which identifies or eliminates a suspect. The effectiveness of forensic support should also be measured in terms of costs and overall budget. The Scenes of Crime Information Management System (SOCIMS) Also in 1991, a software company, CPL Systems, launched a computer package to enable forces to collect this information and produce the reports required in-force and for collection by the recommended central body. The system runs on Windows and is certainly very user-friendly. Reports and tables are easily run off both in standard format and according to the force s own specifications. These factors made the system very popular. It is currently used in 39 out of the 43 forces and is being piloted for use in the Metropolitan Police. At the time of data collection, only one force out of the National Project Team s sample (see section 2) did not use SOCIMS 2

12 INTRODUCTION and therefore was excluded from this study. However it did begin using the system in April Although the fact that most forces are using the same system would seem to make it an ideal starting point for collating national data, this was not found to be the case. As is discussed more fully in section 2 (Methodology), differences in the way forces categorise offences and tests meant that the collation process for this study took many months. Another problem with using SOCIMS which was often mentioned, was the time taken within the scientific support unit (SSU) to enter data onto the system. This ranged from 2 hours per day to almost 2 days per week. Because of this some short cuts are used by most forces. Although the system is designed, in the main, for each item and test to be entered separately, the large number of drugs, alcohol and documents tests would make this an impossible task. Therefore, such tests are routinely entered, in aggregate form, either on a weekly or monthly basis, or by submission only. This can mean that, for example, 100 documents tests can be entered into a field which would normally contain only one test. 3

13 METHODOLOGY 2. Methodology Twelve forces were selected for the ACPO/FSS National Project Team s study. They were chosen to cover forces with high and low crime rates, predominantly rural and urban forces, high and low rate users of the FSS, representatives of all HMIC families of forces and included at least one force attached to each of the FSS laboratories. The majority of forces in England and Wales use SOCIMS to record their use of forensic support. Of the 12 forces sampled by the National Project Team, 11 used this package. These 11 then were taken as the sample for this study. To provide a more rounded picture, two forces which do not use SOCIMS were also visited, and their systems are briefly discussed in section 7. The data used in this report Data were extracted from the SOCIMS databases of the 11 sample forces and covered the full calendar year To bring the forces data together, standard tables were requested from each force. Difficulties immediately arose as PRSU recommended offence categories were not followed. Categories for offences and tests differed widely, and often overlapped. However a standard list of 15 offence categories (to follow PRSU recommendations as closely as possible) and 24 test types (to demonstrate the basic test types) were drawn up. Some information, particularly detail, was lost by this standardisation process. The categories used are listed on the next page: 4

14 METHODOLOGY Offence categories Burglary dwelling Burglary other Theft Theft of/from a motor vehicle Robbery Assault Sexual offences Murder/suspicious death Arson/suspicious fire Fraud Criminal damage Drug offence Alcohol offence Road traffic accident (and motor offences including drink/drug & driving) Miscellaneous Test types Blood alcohol/drug Blood group DNA blood Body tissue Documents Drugs DNA Firearms Fibres Fingerprints Footwear Glass Other physical identification Hair Marks (eg instrument marks,tyre impressions) Paint Saliva Semen Tachograph Toxicology Urine alcohol/drug Fluid alcohol/drug Voice identification Miscellaneous The producers of SOCIMS, CPL Systems then wrote an extraction programme to take data from the complex relational database of SOCIMS onto a simple 2- dimensional ASCII format. A conversion programme was also written to put the forces categories into the new standard format. When the data were received however, it was clear that SOCIMS freefield entry system had created more problems. Such systems allow the person entering the data to type in anything he or she wishes. Therefore even the codes which are used in one force can be entered in many different ways; even using capitals or lower case type will result in 2 different variables being read. This problem meant that each entry had to be cleaned manually before it could be entered onto the database. After cleaning, the information was put onto 2 databases on SPSS for Windows. One database held details of each test performed on an item (referred to in this 5

15 METHODOLOGY report as the tests database ), and the other held data on each submission (referred to as the submissions database ). Nearly 12,000 submissions and over 50,000 tests were recorded. Usually all the items in a case are sent to the laboratory together as one submission. There are occasions however, especially in murder/suspicious death offences where more than one submission is made per case (for example when more evidence becomes available following investigation), but this is relatively rare. The following information was recorded: Submissions database. For each submission; Force Division Case reference Forensic support provider (FSS or other) Laboratory (if FSS) Offence category Number of items sent Number of items tested Date sent to the laboratory Date statement received from the laboratory Cost Evaluation by the Scientific Support Unit Evaluation by the Officer in the case Tests database. For each test; Force Division Case reference Forensic support provider (FSS or other) Laboratory (if FSS) Offence category Test type Item sent Date sent to the laboratory Date statement received from the laboratory Cost Evaluation by the Scientific Support Unit Missing data As different forces consider different information to be vital for management information, not all fields were used by every force. The most commonly underused fields were the officer in the case evaluation and the number of items actually tested by the laboratory. In addition, some forces felt that information on which agencies they used and some costs data were commercially sensitive. Such data were therefore not collected from these forces. Both these factors resulted in a fair amount of missing data, although this was easily controlled for. Each analysis used only data from forces which could provide the necessary information. Thus the number of forces in each analysis ranged from eight to eleven. 6

16 METHODOLOGY Of equal importance was the amount of missing data for which there was no consistent pattern, for example the occasional missing date or cost field. These instances were also excluded from analyses, but in some cases this was not possible. Therefore the individual force totals for costs and time taken should be viewed with a little caution, although percentage, ratio and overall sample data should be reliable. Before the data extraction was carried out, some forces did mention that because of the time it took to enter information onto SOCIMS, their data may not be complete. With the exception of force J, which had a large time period of data missing, items that were not entered appear to have been totally random. 7

17 GENERAL FINDINGS FROM SOCIMS General findings from SOCIMS 1994 Submissions This section shows how forensic science was utilised in 1994 as recorded by SOCIMS. Despite the size and complexity of the two databases, some simple tables can be produced. Perhaps the most obvious start is simply to show the offences for which forensic analysis was carried out. In table 1, the number of submissions for each offence type is listed along with the percentage of forensic work which each offence category accounted for. Table 1. Submissions by offence category Offence Number of submissions Percentage drugs 5, road traffic related 1, burglary other 1, miscellaneous 1, murder/suspicious death 1, sexual offences 1, burglary dwelling 1, assault 1, theft 1, fraud 1, robbery 1, criminal damage 1, theft of/from motor vehicle 1, arson/suspicious fire 1, alcohol 1, Total 11, The most obvious feature to emerge from this table is the high proportion of drugs offences. This is discussed in more detail in section 5. For the sake of simplicity of presentation only three violent offences (murder/suspicious death, sexual offences and assault), and one volume offence (burglary) are considered in the remainder of this report unless otherwise stated. The two burglary categories (burglary dwelling and burglary other) have been combined because forces tended to record them differently so it was not possible to 8

18 GENERAL FINDINGS FROM SOCIMS 1994 differentiate between them reliably. All other offence categories are shown in the appendices. Submission patterns Table 2 below shows the proportion of recorded offences for which forensic material was submitted for testing. Table 2. Notified offences and submissions by force Force Murder/ Sexual offences Assault Burglary TOTAL suspicious death N S% N S% N S% N S% N S% A , , , B , , , , C , , , D , , , , E , , , F , , , G , , , H , , , , I , , , J , , , K , , , TOTAL 1, , , , , N = Number of notifiable offences S = % submitted Table 2 illustrates several relationships between offences and submission rates. First, all forces have a much higher submission rate for violent offences than for burglary. From discussions with SSM s, it appears that the main reason for this is that violent offences against the person are treated as serious crimes and there is less pressure to limit spending on such submissions. However as can be seen, there is still considerable variation between forces submission rates for violent crime, with no readily available explanation. 9

19 GENERAL FINDINGS FROM SOCIMS 1994 Although submission rates are far higher for violent offences than burglary in all forces, there is variation in the extent to which submissions are polarised in this way. Some forces send submissions for a relatively high proportion of their violent offences and a low proportion of their burglaries. There are, however, forces which send submissions for a relatively lower proportion of their violent offences but a higher proportion of burglary. This is shown more clearly in table 3, where the forces displaying this pattern of submissions are shown in bold. Also, the forces with the highest overall number of offences tend to have the highest submissions rate for violent crime, whilst the forces with the lowest overall number of offences (and lowest number of burglary offences) have the highest submissions rates for burglaries. This is again shown by the forces highlighted in bold in table 3. It appears from this, for reasons which are unclear, that some forces have decided to concentrate their forensic submissions on either major or volume crime and in many instances this does not reflect the number of actual offences that are recorded in each category. Table 3. Differences in submission rates by force Force Crime Rate Submission rate violent burglary B high high mid F high mid mid D mid low low K mid high mid J mid mid mid E mid mid mid H mid mid mid A low low mid G low mid high I low mid mid C low mid high Obviously any force submissions policy will affect these figures. Most forces did not have a formal written policy on submissions (apart from the procedures to follow). However three forces did mention an informal policy: 10

20 GENERAL FINDINGS FROM SOCIMS 1994 Force A evidence from burglaries is only sent to the lab if there is a known suspect. Also, evidence is not tested to link scenes, only to link a suspect to a scene. If a suspect subsequently confesses, all evidence is withdrawn from analysis. Force B same policy as force A, but in addition the force has its own lab for certain types of work and priority items. Force E for residential burglaries, only the point of entry is considered for forensic evidence. Such policies shed no light on the rationale behind these submission patterns, although it was suggested during the study, that these patterns might be merely an historic artifact. If so, there is definite scope for the effectiveness of these different approaches to be analysed. As will be seen in section 6, such data cannot be gleaned from SOCIMS at present. How many items are tested? As mentioned previously, each submission usually represents one case, for which one or more items may undergo one or more tests. Although table 2 shows the number of submissions made, not all resulted in any tests being carried out. Some offences and some forces had higher than usual numbers of submissions which never had any forensic work carried out. There are two main reasons for this: The laboratory decides that the material is inappropriate for testing; The case is cleared by another means and so the force cancels the work (for example forces A and B s screening policy above). Table 4 overleaf shows, for each of the four offence types, the mean number of items sent per submission (usually per case) and the mean number of items that were tested. Data are taken from nine forces only, as the number of items returned field was not supplied by force H and not used by force J. Although it is common for more than one test to be performed on an item, this table shows only whether or not any tests were performed on an item. Although the proportion of items tested looks relatively low for murder/suspicious death cases and high for burglary, the effect is easily explained when this table is split by force. In fact three forces, A, I and J, account for almost all of the items sent that were not tested. This low rate of testing can be seen for all recorded offences in force A, as shown in the table in Appendix A. According to the data on SOCIMS, 7% of items sent were not tested. This number is substantially higher than that found in 1987 by Touche Ross (2%). However it was noted then that the proportion of items returned untested was growing rapidly. It is not known whether the entries on SOCIMS are reliable and such a large 11

21 GENERAL FINDINGS FROM SOCIMS 1994 number of items is indeed being returned, nor whether items are returned on scientific grounds or due to staff shortages (as suggested in the Touche Ross report). Table 4. Number of items sent and tested per submission by offence type Offence Mean Mean % Max n Max n Total Total number number items items items number number items items tested sent/ tested items items sent tested case /case sent tested Murder/suspicious death ,782 3,468 Sexual offence ,045 3,321 Assault ,568 3,075 Burglary ,317 6,847 The murder/suspicious death category Murder and sexual offences are the offence categories where multiple submissions are most often made. A manual search revealed that in the murder/suspicious death category, half of the cases had involved one submission and one case had involved 21 submissions. Figure 1 below shows the distribution of submissions per case. Figure 1. Number of submissions per case for murders and suspicious deaths Number of submissions 12

22 GENERAL FINDINGS FROM SOCIMS 1994 To see the true number of items sent per case, the submissions were then amalgamated into cases. Table 5 below shows that the mean number of items sent per case is much higher than the number per submission (Table 4). For clarity, cases with only one submission (which would almost certainly be suspicious death cases rather than murders) are separated. This means that the number of items per submission shown in table 4 is quite a large underestimate of the number of items per case for murder and suspicious death offences. Table 5. Submissions per case for murder/suspicious death offences Mean number of items sent Maximum number of items sent One submission per case More than one submission per case The fact that murder and suspicious deaths are collated in the same category may give a false impression of the true use of forensic science in murder cases. Although it was not possible to separate these categories directly, several SSMs postulated that as suspicious death cases usually only resulted in one submission, and murder cases in more than one, it would be possible to separate the offences on this basis. As figure 1 shows, there is no clear cut-off point to substantiate this proposal. From national figures, it would be expected that around 80 of the cases in this category would be murder cases, but even taking the highest submission rates from the combined category does not give this number of cases. Therefore, it does not seem possible to separate these cases by any means. Were standard offence categories used by every force, this problem would never arise. 13

23 GENERAL FINDINGS FROM SOCIMS 1994 Tests Again, the most obvious start point is to list the type and number of tests performed in 1994 and their relative proportions. Table 6. Number of tests performed by test type Test Number of tests Percentage drugs 16, fluid alcohol/drugs 4, document 4, glass 3, fibres 3, footwear 2, DNA 2, blood grouping 2, miscellaneous 1, firearms 1, semen 1, marks 1, hair 16, paint 16, control 16, body tissue 16, toxicology 16, saliva 16, other physical identification 16, tachograph 16, fingerprints 16, voice identification 16, 20 Total 51, The extremely high number of drugs tests is discussed in section 5. 14

24 GENERAL FINDINGS FROM SOCIMS 1994 In each submission or case, several items may be sent for different types of analysis. SOCIMS is designed for each test to be recorded separately, so the proportionate use of each test for each offence type can be shown. However, for some test types it is common practice for a single test entry to represent several individual tests. For example under the documents test category, just under 1,000 tests are recorded. When these tests were manually sorted, it was found that over 100 actually represented more than one test and usually more than one item. These multiple item entries together accounted for over 900 tests, effectively doubling the number of document tests performed from the original estimate. Similar effects were seen in both the drugs and firearms tests categories, but not in the four offence categories chosen for detailed analysis. Table 7, on the next page, shows the four offence categories already discussed and the percentage of tests in each test category that they account for. Some of the tests which were little used are excluded for clarity. 15

25 GENERAL FINDINGS FROM SOCIMS 1994 Table 7. Proportion of each test type accounted for by each of the four offence categories Murder/suspicious Sexual Assault % Burglary % death % offences % blood alcohol/drug firearms blood group urine alcohol/drug fluid alcohol/drug body tissue saliva semen DNA other DNA blood other physical identification voice identification fingerprints hair fibres footwear paint marks glass toxicology This table throws up few surprises. Intimate samples appear to be tested mainly for violent offences and the main tests used for burglaries are footwear, glass, paint, fibres and tool marks. The body tissue and other physical identification categories do actually overlap because of recording practices in different forces. Both these categories contain nail scrapings and hair combings tests. Facial reconstruction and photofits are in the physical identification category. In addition, some of the body tissue cases are in fact blood, semen etc. samples which were not coded under the 16

26 GENERAL FINDINGS FROM SOCIMS 1994 specific test heading. No fingerprint analyses were recorded for burglaries as these are performed in-force. The main table for all offences is included in Appendix B but some clear patterns are worth mentioning here: The tests used for robbery offences follow a similar pattern to burglary, although saliva and hair tests are used more frequently and footwear tests less often. For thefts of and from motor vehicles, the majority of tests are on fibres and documents (document tests were usually multiple entry items). The majority of tests for arson fall into the miscellaneous category. On manual investigation of the items sent for testing however, nearly 80% were on clothing or footwear. The next main item sent was debris, which appeared in the miscellaneous category because not all forces record this item separately. Items classed as debris are usually burnt items (often wood) which are analysed to find the cause of the fire (usually a test for accelerants). Tests on fibres were split between the fibres and miscellaneous categories for arson offences, in fact fibre tests were more commonly performed than firearms tests. When these data are split by force, some inter-force variations begin to appear, for example: The split between the tests used for violent offences and those used for burglaries is extremely clear in force C, where no intimate tests were used for burglaries and only intimate tests were used for violent offences. In force D, a high proportion of violent crimes had samples sent for tests on hair, fibres, glass and footwear. In most forces, around 10-30% of the tests performed for burglaries were on footwear, but in force G, this figure was almost 70%. For violent crimes, the force which used DNA testing most frequently was G, at 69%, whilst the lowest user was force F at 5.4%. For burglaries, two forces, C and F, did not use DNA testing, and the highest user at 9% was force A. Most forces used DNA testing in about 1% of cases. Since these data were collected, the DNA database has begun operation, and the use of DNA testing will have changed dramatically. 17

27 GENERAL FINDINGS FROM SOCIMS 1994 These inter-force variations are described to show the information which can be gleaned from SOCIMS. Force submission policies do not explain the differences, but it would be interesting to follow up whether, for example, the high usage of footwear analysis in force G had any beneficial effect. Costs Table 8 below shows the cost of forensic work for each force along with the mean cost per submission (usually per case). Force budgets varied in what types of forensic science they covered, but in the main, all forensic support and fingerprint analyses (both external and in-house) were covered, and specialist services such as pathologists and police surgeons were not. Table 8. Costs and budgets for forensic support by force (in descending order of mean cost of submission) Force Total forensic Spend recorded Mean cost % missing budget on SOCIMS per submission F unavailable 1, 922, G 1, 438,400 1, 326, D 1, 498,000 1, 188, B 1,615,000 1,433, I 1, 191,000 1, 140, C 1, 300,000 1, 246, H unavailable 1, 670, J 1, 962,695 1, 14, E 1, 623,000 1, 590, K unavailable 1, 836, A 1, 400,000 1, 1, TOTAL 6,049, The underspend shown in most forces is due to costs that were incurred near the end of the year not yet being entered. The mean cost per submission was calculated excluding any missing data. Although the proportion of budget actually spent by some forces looks extremely low, each force had other accounting methods which showed that they had in fact spent most of their available budget. Why so much costs data are missing from SOCIMS is not known. The percentage missing column shows the proportion of cases where the cost was either not entered, or was entered as 0. Sometimes the Forensic Science Service do not make a charge on a test, as 18

28 GENERAL FINDINGS FROM SOCIMS 1994 they calculate a price for the whole case. However some charge should appear in this database, as the units being considered are whole submissions, which in most instances means whole cases. A regression analysis was conducted to examine the relationship between forces submission patterns and the mean cost per submission. A significant relationship was found (p <.05) showing that forces which had high submission rates for violent offences also had the highest mean cost per submission. This is understandable given that, as table 9 shows below, violent crimes are the most costly offences. The reason for this is that, as shown in table 4, these were the offences for which most items were submitted per case. However the submission pattern only accounted for 50% of the variation (R square = 0.52) in mean cost and therefore some other factors must be present. Table 9 below shows, across all forces, how mean costs vary by offence category. Table 9. Cost of forensic support by offence Offence mean cost per submission murder/suspicious death 1,426 assault 1,193 sexual offences 1,122 burglary other 1,095 arson/suspicious fire 1,027 robbery 1,025 burglary dwelling 1,008 criminal damage 1, 811 theft of/from motor vehicle 1, 803 miscellaneous 1, 571 alcohol 1, 459 theft 1, 457 fraud 1, 344 drugs 1, 203 road traffic related 1, 186 TOTAL 1, 540 NB. A percentage missing column is not included in this table as there was very little variation between offence categories, all having between 3% and 10% of their costs data missing. 19

29 AGENCIES PROVIDING FORENSIC SUPPORT 4. Agencies providing forensic support Market share for forensic providers Following the Touche Ross recommendations, the Forensic Science Service became an executive agency in At the same time, a system of direct charging was introduced. The difficulties that arose from the timing of these changes are discussed in Tilley and Ford (1995), however suffice to say that it was predicted that the FSS was likely to lose a part of their market share in the following few years. This section will look at the usage of the FSS and the combined other agencies in Table 10, below, shows that other forensic providers have made few inroads into the FSS s share of the market. The information is taken from the nine forces that were willing and able to provide these data. Table 10. Submissions and costs by forensic support provider FSS Others No. % No. % Submissions 8, Cost of submissions 4,599,746* , Tests 33, , Cost of tests 4,599,882* , *Slight variations are due to the different ways some forces enter submission and test data onto SOCIMS. Variations between agencies and laboratories Several differences were found between the FSS and other agencies in many performance indicators. Although both tested similar percentages of the items sent per submission, turnaround time and costs did vary. The average time for the FSS to produce statements was around 43 days and for the other agencies was around 15 days. The differences in costs are shown in table 11 overleaf. 20

30 AGENCIES PROVIDING FORENSIC SUPPORT Table 11. Usage, costs and time taken for the most common tests by forensic provider FSS Others % of Mean Mean % of Mean Mean Test type work cost time work cost time load taken load taken (days) (days) fibres DNA blood DNA other blood alcohol/drugs blood grouping marks glass firearms semen footwear fluid alcohol/drugs drugs documents Clearly the other providers mostly supply a niche market in document analysis; the FSS continues to provide the full range of testing. Since document and drugs tests, by any agency, are reported on quickly, this difference in the types of tests performed by the different agencies will make the other providers performance figures look much better than the FSS. However it has to be said that the specialist service in document testing is faster and cheaper than that provided by the FSS. 21

31 AGENCIES PROVIDING FORENSIC SUPPORT There were also variations between the different laboratories of the FSS. The percentage of items tested ranged from 79% at Birmingham to 99% at Aldermaston. The variation in time taken is shown in table 12 below. Table 12. Time taken by FSS laboratory Laboratory Number of tests Mean time taken Aldermaston 2, Birmingham 2, Chorley 17, Chepstow 6, Wetherby 5, Huntingdon 2, Again the difference in turnaround time seems explained by the nature of the tests carried out in each laboratory. The relatively fast turnaround time at Aldermaston was undoubtedly due to the fact that 89% of their work consisted of alcohol and drugs tests (which table 11 has shown have a faster turnaround time). In most other laboratories, this figure was around 40 50% of their work, with glass, footwear and marks tests at around 10% each. The only exception to this pattern was Huntingdon, where firearms tests made up 45 % of the workload. It should be noted however, that forces other than those in this study use these laboratories and the data may look different if all forces were included. Although by no means all factors affecting performance have been considered here, it is obvious that a straightforward comparison between agencies or between FSS laboratories is not possible. The circumstances surrounding forensic support purchasing, provision and recording are complex and possibly too force-specific to enable any simple comparison of performance to be made. 22

32 DRUGS 5. Drugs Submissions and tests data As seen in section 1, drugs accounted for 16,770 tests (32.6% of all forensic tests), and cost forces a total of 983,200 (16% of total costs) in It is therefore worth examining this area more closely. Table 13 below shows how submission and test rates for 1994 compared to notified drugs offences for 1993 (the most recently available calendar year data at the time of writing). Table 13. Submissions and tests by forces notified drugs offences Force Notified Submissions Tests Average offences number of tests/ submission N N % N N B 3, , K 2, , J 2, , E 1, , H 1, , F 1, , G D C , A I TOTAL 16,574 5, , Table 13 shows that a high percentage of drug offences result in a submission being made to a laboratory compared to most other offences. This is explained by the legislative requirement to prove the identity of a drug for a prosecution. Home Office Circular 26/1991 sets out the circumstances in which forensic examination may not be required. Cocaine and related drugs must always be sent for identification, but there are circumstances when this is not necessary for cannabis or heroin and related drugs. 23

33 DRUGS Seizures of cannabis do not have to be sent for forensic examination if: the case is heard at the magistrates court, and the person admits possession and agrees that the drug is cannabis, and an officer experienced in dealing with drugs identifies the substance as cannabis, and it is a small quantity for personal use only and the person pleads guilty. Seizures of morphine, heroin and amphetamine do not need to be sent for forensic examination if: the case is going to the magistrates court or sentencing is at the Crown Court, and it can be tested by an approved drugs testing kit carried out by a specially trained police officer or civilian Scenes of Crime Officer (SOCO), and there has already been an admission of guilt. In order to find the distribution of tests across these three drug classes, a five percent random sample of 755 cases was examined. The results showed that 40% of tests were on cannabis and related substances, 26% on heroin and related substances and 14% on cocaine and related substances. Table 13 also shows that the number of items sent per submission is rather lower in drugs cases than for most offences. There are two possible explanations for this; first, that there are a high number of possession offences where officers find only one item. This could also explain some of the high variation between forces submission rates, as some forces may choose not to target possession offences. Secondly, the practice of entering multiple submissions onto one field may distort the number of items per submission. Some evidence of this was found. In 24% of the random sample of 755 cases, multiple items were entered under one field, with as many as 988 tablets entered in one particular case. Adding together all the multiple entry items increased the number of tests for the sample of 755 by nearly seven times, to 5193 (excluding the above case of 988 tablets, as this was particularly unusual). When this was applied to all the data, it suggested that the actual number of forensic tests carried out for drugs was in the region of 112,400 as opposed to 16,

34 DRUGS Costs Drugs tests are almost exclusively carried out by the FSS, who have standard examination charges for the testing of drugs: cannabis or an extra examination charge: basic examination normal rate: detailed examination: complex examination: The most common tests used were the and 52 tests, however larger submissions raised the mean cost per submission to around 200. Table 14 below, shows, split between the various drugs categories, the spend for each type of drug in 1994 for the eleven sample forces and an estimate for the cost nationally. Table 14. Cost of drugs testing Type of drug Cost for 11 Estimated total forces in cost in England sample and Wales Cannabis and related substances 393,280 1,540,000 Heroin and related substances 255,630 1,000,000 Cocaine and related substances 13,650 1, 53,000 Unknown class 315,130 1,229,000 TOTAL 977,690 3,822,000 Despite the Home Office circular, drugs testing is still accounting for 16% of the national forensic budget. The SSMs who were asked why so much testing was still necessary usually cited cases where the drugs offence was linked to another offence (usually burglary) and the case was therefore being heard at the Crown Court. Under these circumstances, a laboratory test is still needed. 25

35 THE VALUE OF FORENSIC TESTS 6. The value of forensic tests What the evaluation scores mean There are two fields for evaluations in SOCIMS; one for the Scientific Support Unit (SSU) and one for the officer in the case (OIC). The SSU evaluate both the scientific value of individual tests and the entire submission s usefulness to the case. The officer in the case however, evaluates only the submission and considers only the usefulness to the case. The scoring used is from 1 to 4 (as discussed in section 1). The FSS use a different system which is based on a seven point scale: 1 conclusive elimination evidence 2 strong elimination evidence 3 some elimination evidence 4 inconclusive 5 some associative evidence 6 strong associative evidence 7 conclusive associative evidence Opinions differ as to which scoring system conveys the best information. Poor returns from the officers in the case The most glaring omission found from this data set is the OIC evaluations, which are completed in only 30% of cases. By comparison, SSU evaluations are completed in 83% of cases. Nearly all Scientific Support Mangers (SSMs) contacted said that they received only a small percentage of OIC evaluations, and some had been forced to abandon collecting these data. A joint venture by five forces, the North West Forensic Effectiveness Group (NWFEG), has attempted to improve the situation by redesigning their OIC evaluation forms. A pilot study showed that the return rate had increased by 12%, following which the forms are again being improved before being launched. Basic data on evaluations The analysis of evaluation data in this section will, by necessity, concentrate on only those cases for which there are SSU and OIC evaluations. Before proceeding it was essential to check whether this subset of the data would be representative, i.e. that the missing OIC evaluations were not differently distributed to those which were available. First it was noted that the SSU and OIC evaluations in this subset correlated strongly (p <.001). Although this correlation showed that the distribution of SSU and OIC scores were similar, a Chi-square test showed that there were still 26

36 THE VALUE OF FORENSIC TESTS significant differences. In general, OICs tend to score higher than SSUs, with 84% scoring 1 or 2 as opposed to 79% for SSUs. The cross tabulation below shows the relative proportions of evaluation scores given by the SSU and OIC. Table 15. Cross tabulation of SSU and OIC evaluation scores OIC Total 1 1, ,174 SSU 2 1, , , , , ,435 Total 2, ,439 The distribution of scores is more easily seen in the two bar charts, figure 2a and 2b, below. Figure 2a. SSU evaluation scores SSU Evaluation score 27

37 THE VALUE OF FORENSIC TESTS Figure 2b. OIC evaluation scores OIC Evaluation score The differences between SSU and OIC scores could be due to the cases which the OICs choose to score (only 30% of submissions are scored by the OIC). Ignoring drugs, alcohol and road traffic related offences (as these nearly always merit a 1 score) SSU scores were examined, looking for differences between cases where the OIC had scored and those in which s/he hadn t. Again the two groups correlated, but showed significant differences on a Chi-square test. In cases where the OIC had given a score, 64% of SSUs scored 1 or 2, but in cases where the OIC hadn t given a score, only 43% of the SSUs gave a 1 or 2 score. If the drugs, alcohol and road traffic cases are added back, these differences disappear. It is clear from this analysis that the OICs tend to score cases where forensic evidence has been useful to the case and are less likely to complete an evaluation form for cases where the submission has not been helpful. In the analysis which follows in this section, it should be remembered that the OIC scores will be skewed towards the more useful cases. 28