Published in PLOS One on 2026-09-16, this study is presented as an attributed evidence briefing. The excerpts below are the original researchers’ words, reproduced under their Creative Commons Attribution licence. Health Signal has selected the abstract and, where needed, opening background paragraphs; the complete methods, results, limitations and references remain in the linked paper.
Original authors: Farai Nyabadza
Source: PLOS One • DOI 10.1371/journal.pone.0356366
Read the complete primary study ↗ · Creative Commons Attribution licence
From the researchers
Abstract
Crime remains a persistent socio-economic challenge in South Africa, where the incarceration of petty offenders often exacerbates criminal behaviour. Empirical evidence suggests custodial sentencing for minor offences may accelerate progression to serious crime due to exposure to hardened offenders and criminogenic prison conditions. To investigate this, we develop a compartmental ODE model tracking eight population states: susceptibility, petty and serious crime, custodial and non-custodial sentencing, rehabilitation, and relapse pathways. In particular, the model has an explicit non-custodial sentencing compartment, positioned in a distinct community-supervision stratum that is neither the general community nor the prison system, enabling direct comparison of custodial and non-custodial policy scenarios. The model is parameterised using the South African crime and prison data. Sensitivity analysis shows that sentencing rates, rehabilitation efficacy, and relapse probabilities drive long-term dynamics. Numerical simulations reveal that over-reliance on custodial sentencing perpetuates recidivism and incarceration, while prioritising non-custodial disposals and rehabilitation reduces both ℛ0 and CCR. Findings indicate that indiscriminate incarceration of petty offenders entrenches criminal cycles. Evidence-based interventions focused on rehabilitation and relapse prevention offer durable crime reduction. This quantitative framework evaluates justice policies, highlighting reforms that integrate deterrence with effective rehabilitation.
Introduction
Recent data from the South African Police Service (SAPS) for the 2022/2023 reporting period document a marked escalation in violent criminal activity, characterised by a substantial rise in cash-in-transit heists [1]. Concurrently, a surge in mass shooting incidents underscores the intensification of high-impact violent crime across the country [2]. While these phenomena attract the greatest public and policy attention, petty crimes remain pervasive and exert a substantial influence on the broader criminological landscape [3]. SAPS statistics for the same period indicate that petty offences, primarily theft and burglary, accounted for between 60% and 75% of all reported criminal cases, while serious crimes, including aggravated robbery and homicide, continued to impose a heavy societal burden, with more than 27,000 homicides recorded in 2022/2023 [1].
Crime, encompassing both minor (petty) and major (serious) offences, constitute a multifaceted and enduring challenge to global societal stability. Petty crimes, typically classified as low-severity infractions, include acts such as shoplifting, vandalism, and possession of small quantities of illicit substances [4]. Serious crimes, by contrast, involve high-severity offences such as armed robbery, assault, and homicide [5]. Within the South African context, both categories are highly prevalent and together contribute to elevated public safety concerns and deepening doubts regarding the efficacy of the criminal justice system.
Incarceration has historically been justified on the grounds of rehabilitation and deterrence [6], yet accumulating evidence challenges its effectiveness. Research suggests that imprisonment may not only fail to reduce crime but can, under certain conditions, intensify criminal behaviour [7]. In South Africa, chronically overcrowded prisons routinely house minor offenders alongside hardened criminals [8,9], creating criminogenic environments that substantially elevate recidivism risk [10]. This dynamic is consistent with the Prison Industrial Complex thesis, which holds that the carceral system sustains, rather than disrupts, cycles of criminality within broader socio-economic structures [11].
Reading this evidence
Use the full paper to check the study design, participant selection, comparator and outcome definitions before drawing a practical conclusion. An association does not by itself show cause and effect. A reported performance measure needs its denominator and uncertainty. A finding from a particular facility, sample or time period should retain that scope when it is discussed elsewhere.
This briefing makes the source accessible within the wider financing & policy desk. It does not assess an individual patient or certify a product. When considering relevance to another health system, examine the original authors’ account of context and limitations, then seek local implementation evidence. The related reporting below provides other studies to read alongside this one; it is a topic connection, rather than a claim that their results are directly comparable.
© 2026 Farai Nyabadza. Excerpts reproduced under CC BY. Selection, formatting and contextual notes by Health Signal. The researchers are the authors of the source study, not members of Health Signal’s staff.
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