CA API Estimator

Description: This is an abstract for the API Estimator, which applies Academic Performance Index(API) formulas to released data to calculate estimated Base API and/or Growth API scores before California Department of Education has released actual API scores.

Purpose: Identifies how students scored in each performance level for any STAR test taken and its subgroups, and how that performance likely impacted API.

Navigation: Reports > List Reports > Prebuilt



Who is the intended audience?


What data is reported?

# of students scoring in each performance level for each STAR test administered (overall and by subgroup) with calculations and estimated Base API or Growth API (run report either way) for a particular year.

How is the data reported?

The report is run for a particular site or district as a whole, each grade level/span has its own section, and subgroups are broken down within these sections.

What data needs to be loaded in Illuminate to get an accurate estimate?

STAR data for the year the report is being run must be imported into Illuminate.  For example, for the 2013 Growth API estimate, the full 2013 STAR data is needed.

If the API estimate is for a high school, CAHSEE results from February, March, and May administrations for the school year for which the report is being run must also be imported into Illuminate.

Does the API Estimator factor in inclusion/exclusion rules?

Yes, we do factor in the inclusion/exclusion rules, including the continuous enrollment data. We do have some disagreement between our numbers and the state so they are not exact, but pretty darn close.

How close should I expect the estimator to be?

Over 80% of schools tested were within +/- 2 points on their 2011 Base API (with over 1/3 of all schools geting exact matches). Less than 5% of schools tested had differences of 10 points or more. 2011 base accuracy should be a fairly accurate predictor of the 2012 Growth API accuracy since both calculations use the same logic.

If a student dropped off the roster at the end of the last school year, for example, say they exited on the last day of school (after being enrolled the whole year), are they still included in the API?

Yes, they are still included.

NOTE: The general math rule adjustments were removed for the 2013 API calculation. There are however a few OTHER conditions that would cause a student to fall into the Math 200 point assignment. Here's a few specific examples.

1.) A modification was used 

2.) The student cheated or did not complete the math assessment.


  • If you try to access the API Estimator and no sites are listed in the site selection menu, the school/district needs to edit the site(s) under Site Management and fill in the State School ID field with the full 14-digit CDS code for the school. Often the CDS code is shown with dashes, but it should be the 14 digit code with no spaces or dashes. For example, 30-66670-6030324 is what is normally reported, but it should be input as 30666706030324.
  • If the CDS code is filled in, but the site still doesn't show in the menu, they need to verify that the site has the correct CDS code, and that the raw data file from the state actually refers to that same CDS code.
  • If you identify a discrepancy, please take a screen shot of the estimate from Illuminate, compare it to DataQuest (if available), and pass the info to our help desk via email.
  • This report features estimates; official API scores are posted at Also, you cannot judge multi-year growth by comparing multiple API scores over time; rather, only a single year’s comparison between the Base API and Growth API can show improvement, and those differences (e.g., +3 growth, followed by +5 growth, etc.) may be compared over time.
  • For more specific details on the API, please visit and view the Information Guide ( for the current State reporting cycle.