Quantitative + Mixed methods/ Sampling
Systematic sampling
Use a random start and a planned selection interval
Systematic sampling selects units at a regular interval after a random start from an ordered frame. Appropriate variants handle fractional intervals and unequal probabilities. Ordering can spread a sample efficiently across the frame, but periodic patterns aligned with the interval can damage precision. A single systematic sample often provides limited information for unbiased design-based variance estimation.
WHEN IT FITS
Use for ordered registers, production flows or administrative records when the ordering is understood and interval selection makes field or computational work simpler.
Strengths
- Simple to execute and audit
- Can spread observations across a well-ordered frame
Limitations
- Periodicity can create poor or misleading samples
- Variance estimation needs care with only one random start
Know the boundary
Selecting every tenth record from a convenient starting point is not automatically probability sampling.
USED ACROSS
Banking & financeBusiness & MBAPsychologyComputer scienceEducation