Design and validation of a rapid visual processing measure for screening reading difficulties in early childhood.

As the development of visual processing abilities is known to precede the development of reading abilities, identifying visual measures that reliably correlate with reading measures has tremendous theoretical and practical importance. A major challenge in addressing this question empirically is developing reliable behavioral measures for developmental studies, because most tasks are not equally reliable across different age groups and require iterative design changes to ensure that the measure reliably indexes the intended construct across the developmental span. Here, we present a series of studies that show how to iteratively modify a behavioral task by data-informed task changes and the use of item response theory to reduce task redundancies and develop a fun, fast, reliable, and easy-to-deploy web-based measure for K/1/2-graders in school settings. Our results show, in a large, diverse, and representative sample (N ~ 1,550), that the ability to rapidly encode visual information reliably correlates with reading outcomes at the end of the academic year. The developed measure offers the potential for use as an early screening tool to identify children at risk for developing future reading challenges.