observer bias
blind observer
operational definition
reliability
test-retest reliability
inter-judge agreement
inter-observer reliability
internal consistency
subject biases
social desirability bias
demand characteristics
Hawthorne effect
environmental manipulation
instructional manipulation
stooges
correlation coefficient
factor analysis
factor loadings
construct validity
content validity
convergent validity
discriminant validity
known-groups technique
experimenter bias
manipulation check
placebo treatment
standardization