השוואת שיטות

	סוגי מערכי מחקר	שיטות דגימה במחקר
תחום	מתודולוגיית מחקר	מתודולוגיית מחקר
משפחה	Process / pipeline	Process / pipeline
שנת המקור	1963	1950
הוגה השיטה	Donald T. Campbell and Julian Stanley (1963); William Shadish, Thomas Cook, & Donald Campbell (2002)	William G. Cochran and Leslie Kish (1950s–1970s)
סוג	Framework	Framework
מקור מכונן	Campbell, D. T., & Stanley, J. C. (1963). Experimental and Quasi-Experimental Designs for Research. Rand McNally.	Cochran, W. G. (1977). Sampling Techniques (3rd ed.). John Wiley & Sons.
כינויים	research designs, experimental and observational designs	sampling strategy, sampling design, probability and non-probability sampling
קשורות	3	3
תקציר	Research design is the overall structure and strategy of a study, encompassing decisions about how to collect, organize, and analyze data to answer research questions. Major design types include experimental (randomized controlled trials), quasi-experimental (non-random assignment), observational (no manipulation), and qualitative (exploratory, interpretive). Donald T. Campbell and Julian Stanley's 1963 seminal work established systematic terminology for internal validity threats in each design type. Modern classifications (Campbell et al., 2002; Creswell & Plano Clark, 2011) also include mixed-methods designs combining quantitative and qualitative elements.	Sampling is the process of selecting a subset of individuals, observations, or units (the sample) from a larger population to study. Sampling methods are broadly classified into probability (random) and non-probability (non-random) approaches. Probability methods—random sampling, stratified sampling, cluster sampling, systematic sampling—enable statistical inference to the population and allow calculation of confidence intervals and margins of error. Non-probability methods—convenience, purposive, snowball, quota sampling—are practical for exploratory or qualitative research but do not support formal statistical generalization. Cochran's Sampling Techniques (1977) and Kish's Survey Sampling (1965) are foundational references; modern applications span surveys, experiments, qualitative studies, and clinical trials.