Measurement error in pre-school children’s emerging knowledge and skills. A case study from the UK

Abstract

ABSTRACT Many studies attempt to measure pre-school children’s emerging knowledge and skills. While such data are of great value to researchers, it also brings significant measurement challenges. Unfortunately, in most secondary analyses, measurement error in these data is ignored. This paper consequently presents a case study documenting the magnitude and structure of measurement errors in three-year-olds Bracken School Readiness test scores within the UK’s Millennium Cohort Study. The analysis illustrates how measurement error in three-year-olds test scores is substantial, non-classical and varies by factors such as children’s behaviour during the test and the survey fieldworker assigned. It is then shown how ignoring these measurement errors could lead to appreciable changes to one’s understanding of pre-school children’s knowledge and skills. The paper concludes by making recommendations for groups collecting and analysing pre-school assessment data.