Discuss (a) Snowball sampling

Census = the complete enumeration — every unit of the population studied (the national census's own model: the every-ten-years count; the courts' full docket audit). Strength: totality (no inference risk). Limits: the cost, the time, the organisation — rarely feasible in legal research. Sampling = the representative part for the whole: the probability samples (the simplerandom — the lottery; the systematic — every kth unit; the stratified — the population's layers sampled proportionately: the judges-by-bench, the prisoners-by-offence; the cluster — the geography's units: the courts-by-district) and the non-probability samples (the convenience — the accessible; the purposive/judgement — the expert selection: the key informants; the quota and the snowball — the referral chain of hidden populations: the trafficked, the released prisoners). The exam's vocabulary: population, sample, sampling frame, sampling error, representativeness; the sample-size's logic (the precision-vs-cost trade); the snowball's ethics (hidden populations, sensitive data).