Programme evaluation, particularly with a quasi-experimental design, provides limited opportunities for sampling because the numbers going through programmes are relatively small. It should be remembered, however, that even where all the programme participants are included in an evaluation, they still technically constitute a sample rather than a population – in effect an accidental sample because they just happen to be in the right place at the right time! Sampling procedures may well be necessary, however, to obtain a suitable comparison group. Here, the first decision is whether to obtain a ‘matched’ group where each member of the comparison group is matched on key criteria such as age, sex, offence, OGRS, to a member of the programme group. This is frequently impractical and so an alternative group is chosen. This is frequently a sample, chosen because they meet key criteria, for example they were appropriate for the programme but not given an appropriate sentence by the court.