State Rank, DFS*, and Percentiles
Since the transition to Common Core in the state of California, CCSA has created and used the Distance from Standard (DFS) to help schools and parents better understand SBAC scale scores and interpret growth. In 2017, the California State Board of Education adopted the same methodology used by CCSA to create this metric state wide as one of several accountability metrics. DFS is a measure that compares a school's Smarter Balanced (SBAC) English Language Arts and Mathematics scale scores by grade to the state standard for "met". The score that is produced means that the average student in the school scored that many scale score points above or below the "met" standard.
We believe that rather than using a percent met or exceeded measure that incentivizes schools to only focus on "bubble students", the DFS instead encourages schools to help each student raise his or her score as high as possible each year. To further operationalize this information and increase its use and understanding by stakeholders, CCSA has translated the DFS scores at the school level into decile ranks which we refer to as State Rank. These decile ranks allow for an immediate understanding of how each school is performing relative to other schools in the state on standardized tests with a 1-10 score or ranking.
How is Distance from Standard calculated?
Because DFS is averaged by grade and subject, this enables fair comparisons across all grade spans and subgroups. Students receive a score on SBAC assessments which fall into one of four levels. Level 3 is called "Standard Met" which has been set as the goal for all students to achieve by the state. The scores reported publicly by the state give school and grade level averages. For the calculation of DFS, a school's average SBAC scale scores are compared across grade and subject to the minimum standard scale score for the achievement level 3 or Standard Met (see more on the SBAC scale score ranges). The difference between a school's actual average score and the met score is then weighted by the percent of test-takers in each grade. These weighted differences are averaged across subject and grade to obtain a single DFS per school.
The DFS produced by the state is for grades 3-8 and separated by subject. CCSA's estimation of DFS occurs after raw SBAC scores are released and prior to the release of the confirmed DFS. This estimation includes a weighted average of grades 3-8 and 11 and combines both subject tests to produce an overall school level score. CCSA's estimated DFS can be slightly different than the DFS published in the Dashboard as CCSA's measure is calculated based off of the CAASPP raw files released by the state in the fall of each school year and does not account for student's continuous enrollment status. The Distance from Standard calculation accounts for student mobility and is calculated from the data files released with the update of the California Dashboard in the winter. In order to get charter schools data they can use toward their renewal petitions and because the estimated DFS and DFS are highly correlated, CCSA produces an estimated DFS when the data is available and updates all data points with DFS at the point we are able to do so.
How are State Rank and Percentiles calculated?
After DFS is calculated, CCSA then places all schools in a lowest to highest rank order to produce a statewide percentile on a scale of 1 to 100. It is from this percentile that we determine the bottom 5% of all schools which are asked to participate in a Multiple Measure Review regardless of their performance on the other metrics within our performance framework.
We then take these percentiles and bin them into 1 to 10 ranks. For example, if a school is in the 6th percentile, it would be given a State Rank of 1. Whereas a school in the 92nd percentile would be given a State Rank of 10. CCSA does not produce DFS percentiles or State Rank for schools that are DASS, Alternative, or that have fewer than 30 valid scores.
*An estimation of Distance from Standard is used when the confirmed Distance from Standard published by the state is unavailable.
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