尽管这些数字很高，但仍有理由相信实际数字可能会更高。reconvictions不代表所有人，可能再次犯罪。利普西，兰登伯格& Chapman（2003），例如，指出匿名自我报告的研究经常发现再犯比官方重新犯罪的统计表明率较高。斯派塞和萃（2004）指出，然而，自我报告的研究依赖于被告的诚实，所以有其自身的缺陷。进一步的批评由Lipsey兰登伯格& Chapman（2003）是重新犯罪率的数字-一个人要么再被定罪或不-而事实是任何康复的作用可能导致严重的违法行为将减少。重新犯罪也不应的结果，唯一的衡量标准，还有其他的一个人生活的重要方面，可以表明其程度的康复，例如，他们的就业状况和心理健康。在尝试康复作出概述由下议院内政事务委员会（hchac，2004）。监狱人口正在迅速上升，在英国和2004的十年前增加了25000名囚犯在美国和威尔士。2004四月，监狱人口达到75544（hchac，2004），有史以来的最高数字，的确率最高的人均被监禁在欧洲。这无疑导致了监狱人满为患的创纪录水平，在英国和139个监狱中，有82所监狱人满为患。（2004）看到的hchac监狱人满为患，为面向康复方案的交付和情况很可能会持续相当长的一段时间最大的问题。
Despite these numbers being high, there is a reason to believe the actual figures might be higher still. Reconvictions do not represent all the people that might reoffending. Lipsey, Landenberger & Chapman (2003), for example, point out that anonymous self-report studies frequently find higher rates of reoffending than the official reconviction statistics suggest. Spicer & Glicksman (2004) point out, however, that self-report studies rely on the honesty of the respondent, and so have their own flaws. A further criticism identified by Lipsey, Landenberger & Chapman (2003) is that reconviction rates are digital - a person was either reconvicted or not - whereas the reality is that the effect of any rehabilitation may cause less serious offences to be committed. Reconviction should also not be the only measure of outcome - there are other important aspects of a person's life that can indicate their degree of rehabilitation, for example, their employment status and mental health.The context in which attempts at rehabilitation are made is outlined by the House of Commons Home Affairs Committee (HCHAC, 2004). The prison population is rising quite rapidly with an increase of 25,000 prisoners in the decade preceding 2004 in England and Wales. In April 2004 the prison population stood at 75,544 (HCHAC, 2004), the highest ever figures, indeed the highest rates of incarceration per head of population in Europe. This has unsurprisingly lead to record levels of overcrowding in prisons, with 82 of the 139 prisons in England and Wales suffering from overcrowding. The HCHAC (2004) see prison overcrowding as one of the biggest problems facing the delivery of rehabilitative programmes and a situation that is likely to continue for some considerable time.