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Strengths and Weaknesses of Basic Sampling Techniques Table 11.3 Technique Nonprobability Samph'ng Convenience sampling Judgmental sampling Quota sampling Snowball sampling Pmbabilig: sampling Simple random sampling (SRS) Systematic sampling Stratied sampling Cluster sampling 2007 Prentice Hall Strengths Least expensive, least time-consuming, most convenient Low cost, convenient, not time-consuming Sample can be controlled for certain characteristics Can estimate rare characteristics Easily understood, results projectable Can increase representativeness, easier to implement than SRS, sampling frame not necessary Include all important subpopulations, precision Easy to implement, cost effective Weaknesses Selection bias, sample not representative, not recommended for descriptive or causal research Does not allow generalization, subjective Selection bias, no assurance of representativeness Timeconsuming Difcult to construct sampling frame, expensive, lower precision, no assurance of representativeness. Can decrease representativeness Difcult to select relevant stratication variables, not feasible to stratify on many variables, expensive Imprecise, difcult to compute and interpret results 11 Choosing Nonprobability Vs. Probability Sampling Table 11.4 Conditions Favoring the Use of Factors Nonprobability Probability sampling sampling Nature of research Exploratory Conclusive Relative magnitude of sampling Nonsampling Sampling and nonsampling errors errors are errors are larger larger Variability in the population Homogeneous Heterogeneous (low) (high) Statistical considerations Unfavorable Favorable Operational considerations Favorable Unfavorable