Give two examples of measurement error sources in developmental assessments.

• A. Observer bias and cultural bias; test-retest variability; environmental distractions
• B. Random sampling error
• C. Data entry mistakes only
• D. Measurement of reliability

Answer: (A)

Measurement error in developmental assessments comes from factors beyond a child’s true abilities that distort scores. Two strong examples are biases tied to who is measuring and how culture fits into the test, and fluctuations in performance across separate administrations. Observer bias happens when an examiner’s expectations or beliefs color scoring or interpretation, so the child’s score reflects these biases rather than actual ability. Cultural bias occurs when test content or administration assumes knowledge, language, or norms from a particular culture, making items easier or harder for children from different backgrounds and introducing error. Test-retest variability is a reliability issue: a child’s performance can naturally vary from one session to another due to sleep, mood, or fatigue, making scores less stable. Environmental distractions, such as noise or uncomfortable testing conditions, add random interference and reduce precision, contributing additional measurement error.

Other options miss the mark because random sampling error concerns who is in the study rather than how an assessment measures a child, data entry mistakes are data-handling issues rather than measurement problems with the instrument, and reliability is the property we assess to understand measurement error, not a source of error itself.