A discrete-time survival study of drug use and property offending : implications for early intervention and treatment

Apart from any fair dealing for the purpose of private study, research, criticism or review, as permitted under the Copyright Act 1968 (Cth), no part of this publication may in any form or by any means (electronic, mechanical, microcopying, photocopying, recording or otherwise) be reproduced, stored in a retrieval system or transmitted without prior written permission. Inquiries should be addressed to the publisher. Please note: minor revisions are occasionally made to publications after release. The online versions available on this website will always include any revisions. Executive summary v Introduction 1 Methodological context 5 The drug use careers of offenders study (DUCO) 6 Survival analysis 7 The reconstructed data 8 Results 12 Describing the data: the uncontrolled baseline hazard 13 Modelling the data: the effect of age and Indigenous status 15 Building the model: the effect of drug use 17 Extending the model: the effect of drug use over time 20 Understanding the model: exploration through prototypes 21 Understanding the model: implications for the theories 33 Assessing the model: exploring the limitations 34 Conclusion 36 Appendix 40 Bibliography 45 Tables Table 1: Sample person-level data 9 Table 2: Sample person-period data 9 Table 3: Sample person-period data 10 Table 4: Descriptive offending indicators among property offenders 11 Table 5: Life-table of years to escalation among property offenders 14 Table 6: Fitted discrete-time hazard model and uncontrolled baseline hazard model 16 Table 7: Prototypical odds and hazard in time period one (T 1) – Models B1 and B2 19 Table 8: Fitted prototypical odds and hazard values in time period one (T 1) 23 Table 9: Fitted prototypical odds and hazard in time period one (T 1) 26 Table 10: Fitted prototypical odds and hazards by time period of illicit drug use onset 32 Table 11: Descriptive offending indicators among property offenders (percent) 34 Table A1: Fitted discrete-time hazard model to the age of transition to regular property offending 41 Table A2: Fitted discrete-time hazard model to the age of transition to regular property offending 42 Table A3: Fitted discrete-time hazard model to the age of transition to regular property offending 43 Table A4: Fitted discrete-time hazard model to the age of transition to regular property offending 44 iv Figures Figure 1: Uncontrolled hazard function of years to escalation among property offenders 14 Figure 2: Uncontrolled survivor function of years to escalation among property offenders 14 Figure 3: Fitted hazard functions …