The study addresses the effects of piloting methods on the reliability and cross-cultural comparability of the measurement of stereotypes. A gender roles instrument from the European Values Study, an ageism instrument, and children stereotypes from the International Social Survey Program were piloted in German and American English and revised based on findings from cognitive interviews, web probing, and expert reviews involving national experts or additionally cross-cultural experts. The original and each piloted version were randomly assigned to respondents in Germany and the U.S. using an online survey and quota samples. The original gender roles and children stereotypes instruments did not face configural invariance and reliability was insufficiently low. The results show that piloting methods can increase insufficient reliability. Measurement invariance could be improved by piloting methods, but effects varied by the type of revisions implemented. Cross-cultural expert reviews and web probing provided more consistent results than other methods. A combination of methods would be optimal to improve reliability and measurement invariance.