All About the Data – Understanding CTP Norms

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CTP Norms Fall 2022

As the 2022-2023 school year gets underway, we want to update you on the latest with CTP norms and explain how we developed the current CTP norms in relation to pre and post-pandemic data.

CTP norms for the fall 2021 test administrations were frozen due to anomalies in the fall 2020 data (e.g., low volume, non-representative samples, and COVID disruptions).

Norms were unfrozen in the fall of 2022 given:

  • the desire for members to understand performance in relation to the pandemic context, and
  • a rebound in test taking that occurred as members adapted to schooling during the pandemic.  A similar update to CTP norms was made in spring 2022.

The fall 2022 update uses a ‘four-year rolling norm,’ meaning the data used to construct the norms includes tests administered in the fall from 2018, 2019, 2020, and 2021.  This timeframe splits the pre-pandemic and pandemic years evenly; however, volume from the pandemic years reflects only about 35% of the tests included in the data set (due to lower testing volume during the pandemic).  

When we compared Independent Norm means for pandemic years to pre-pandemic years, we found that pandemic means were about 2% lower.  There were some exceptions in Levels 9 and 10 that we believe were due to more differences  in the samples of students who took these exams (i.e., changes in the composition of schools taking Levels 9-10), as opposed to the influence of the pandemic.

When we compared the new four-year rolling norm that included pandemic data to the ‘frozen norm’ that was created before the pandemic, we found that students with the same scale score had percentiles that were typically 1-3 points higher.  Percentiles were typically about one point higher in grades 2-9, and 3 points higher in grades 10-11, with half of scores showing percentiles that were higher by 0-4 points.  (There were sometimes exceptions here too, particularly in grades 10-11 for certain subtests.)  We believe the updated norms are more valid and a more useful source of interpretative information for this year’s CTP results because they reflect performance changes that have occurred among ERB test takers.

Summary

There were dramatic impacts to testing during the pandemic that led to ERB “freezing” CTP norms.  Now that testing behavior has more or less returned to a new normal, ERB is unfreezing norms for the fall 2022 CTP administrations.  (We conducted a similar update for the spring 2022 administrations.)  The fall 2022 norms utilize a mix of pre-pandemic and pandemic data.  Since the students in this norm group performed slightly worse than the pre-pandemic norm group, students with the same scores will have slightly higher percentiles.  We believe these percentiles are a better reflection of current student performance and thus provide more meaningful information to guide score interpretation. 

https://erblearn.org/understanding-erbs-updated-norms/
Watch this recorded webinar for more on CTP norms

Join us for office hours later this fall and get an in-depth explanation of norms and how to better understand your data.

  

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