Variability: Human nature and its impact on measurement and statistical analysis.

•Variability is a human nature and large or small variability could directly impact our measurement and statistical data analysis practice.•If not handle correctly, variability could lead to incorrect conclusion or misleading statement on research findings.•Using real and hypothetical data, common errors in measurement and analyzing of variability were illustrated and how to address the errors were highlighted.•There is a call for improving in measurement techniques and better statistical training for handling variability.