Infancy researchers need to change the way they develop their measures: A comment on Byers‐Heinlein et al. (2021)

In their article, Byers‐Heinlein et al. (2021) propose six solutions to create more reliable measures for infancy research. Whereas some of their solutions focus on changing the culture in the field (reporting on reliabilities, choosing measures based on psychometrics instead of conventions or face validity, conducting research on psychometrical qualities of measures), other solutions directly relate to the implementation of tasks or data analysis (collecting additional data, exclusion of unreliable trials, more sophisticated analyses). In this commentary, we highlight challenges in the assessment of measurement reliability and why the characteristics of current measures in infancy research make it difficult to add additional trials as suggested by Byers‐Heinlein and colleagues. We then propose how the field of infancy research could move forward by changing (1) the way measures are developed and (2) what kind of measures are developed. Highlights Different types of measures require the calculation of different types of reliability: retest reliability, parallel test reliability or internal consistency. Increasing internal consistencies by the addition of trials is often not feasible. The collaborative development of standardized measures improves measurement reliability, increases the replicability of results and fosters comparability across studies. Instead of measures with few trials of long duration, infancy researchers should make use of technological advances and develop measures that operate on shorter time scales.