The purpose of the Validity Studies is to gather evidence about the appropriateness of Istation’s Spanish Assessments for Grades PK-5. Evidence will be collected to align with the Technical Standards as specified on the National Center for Response to Intervention (NC-RTI) tools chart for universal screeners and National Center on Intensive Intervention (NCII) tools chart for progress monitoring tools.


Imagination Station



Principal Investigator

Dr. Leanne Ketterlin Geller


Evidence will be gathered for the following indicators:

  • Reliability of the performance level and reliability of the slope
  • Criterion-related evidence as compared with nationally recognized standardized tests and the state accountability assessment. Because students in K-2 do not take the state accountability test, an appropriate criterion will be administered.
  • Criterion-related evidence for relevant subpopulations and conduct relevant bias analyses
  • Classification accuracy of the performance level
  • Predictive utility of Istation’s Assessments as compared to one competitor’s assessment
  • Comparability of alternate forms
  • Calculate acceptable rates of improvement and end-of-year benchmarks using available data
  • Calculate sensitivity to student improvement using comparison data between groups
  • Determine if the use of the ISIP Assessments results in improved student achievement


We will conduct the following analyses to gather relevant validity evidence:

  • Correlations between ISIP Assessments scale score and criterion measures
  • Logistic regression models using ISIP Assessments performance level and criterion measures
  • Hierarchical linear modeling (HLM) to estimate students’ growth trajectories
  • Area under the curve using the Receiver Operating Characteristic (ROC) curve
  • Linear regression models to predict unique contribution of ISIP Assessments


By gathering evidence to evaluate the validity of the uses and interpretations of Istation’s Spanish Assessment, we anticipate providing test users with valuable information for determining the trustworthiness and meaningfulness of the test scores for making universal screening decisions.