Sampling bias in fieldwork occurs when the sampling method:

• A. Randomly selects from entire population
• B. Systematically favours or excludes certain groups
• C. Measures sample repeatedly
• D. Uses secondary data

Answer: (B)

Sampling bias happens when the method used to select the sample systematically favours or excludes certain groups, so the sample isn’t representative of the whole population. In fieldwork, this means if you only collect data from easily reachable sites or from a particular group, you’ll miss other parts of the area and your findings won’t reflect its true variety. That’s why describing a method that systematically favours or excludes groups is the best way to define sampling bias.

Randomly selecting from the entire population aims to avoid bias, so it wouldn’t be biased sampling. Measuring the same sample repeatedly affects reliability and precision rather than who gets included. Using secondary data isn’t about the act of selecting a sample in the fieldwork itself, though biases could exist in the original data collection.