It’s annual testing time again at school and letters are coming home about the importance of good sleep and good food for optimal test performance. In our region, the test of choice is the SBAC, which stands for Smarter Balanced Assessment Consortium. After getting their (largely uninformative) family score reports by mail last year, I did a little digging to see if I could get more context for my kiddo’s scores. A little sleuthing turned up their 264 page Technical Manual from which I gleaned a whole lot more about the test. I’m hoping this post will save you some time if you’d also like to know the answers to:

1. How does my student compare (on a percentile scale) to other classmates?
2. How does my student compare to students one or more grade levels behind or  ahead?
3. How do his middle school scores compare to the scores among soon-to-graduate high school students?

The relevant tables I needed to look at in the report were Tables 5.3, and 5.70 through 5.76. From those I constructed the following summaries and illustrations. You can download the complete tables with all the demographic breakouts here.

Recall that percentile scores indicate what percent of the population scored below the given score. The 90th percentile for 3rd graders in ELA/Literacy is 2528 which means that 90% of test takers in the third grade scored below 2528 and 10% scored above 2528.

A few things to notice…

1. The color coding draws attention to the fact that top scoring 3rd graders are getting essentially the same test scores as low performing 11th graders. I was expecting to see overlap between primary & middle school scores and also an overlap between middle & high school scores, but I was extremely surprised to see so much overlap in scores from primary to high school! I think that parents and educators generally only get score reports and calibration values for a single grade, so unless you have kids in multiple grades or know to look at the Tech Manuals, this would remain hidden.
2. The score spread between the 10th and 90th percentile doesn’t change much across 8 years of schooling. In point of fact, it gets slightly wider for both ELA and Math by about 50 points. Theory in public education would argue that kids come into the school system with lots of different early childhood and pre-K experiences, but that over the course of 12 years of formal schooling these gaps will close. This data says just the opposite. The gaps measured in 3rd grade persist, and widen.

Plotting the data help draws attention to these 2 points which I doubt the SBAC people, nor the schools would want emphasized.

Notice that the line charts include the Lowest Obtainable Scaled Score (LOSS) and Highest Obtainable Scaled Score (HOSS) derived from Table 5.3. These extremes were omitted from the tables above. Anyone with kids in the 0-10 or the 90-100 range knows all too well that these kids need a different school experience and these charts help illustrate why. The highest scoring 3rd graders are already well above the median 11th grader with 8 more years of classes to sit through. The lowest 11th graders would barely reach the 10th percentile as a 3rd grader.

Focusing attention on the shaded area, you can visually see the amount of overlap in scores from 3rd to 11th grade. You can also see that the shaded region remains roughly the same height, widening just a tad toward the right, and widening more for Math than for ELA.

Case for Ability-based Grouping

Let me sum up with a plug for ability-based grouping for academic subjects.

Why do we find it normal to see an advertisements for “Beginner Tennis Lessons Ages 8-12” or “Intermediate Piano Ages 13-18”, but we find it unacceptable to do the same for academic subjects (outside of Foreign Languages)? We insist on grouping children by age, rather then ability and having them all plod through 12 years of education in lock step.

As an avid adult learner, I like to imagine what the pubic reaction would be if one of the major online learning platforms such as Coursera offered courses by age and you couldn’t advance to Biology for 43 year-olds until after you completed Biology for 42 year-olds AND had a birthday. I’d expect the public to find it ridiculous and insist that they be allowed to move through the content as they mastered it.

This is the same public that sends their kids to X grade every day without questioning the basic principle of age-grouping versus ability-grouping.