KnowledgeBases > Understanding Data
The No Child Left Behind Act places an emphasis on student academic achievement data and using it as a means to measure improvement over time. Quantifiable metrics are critical in the determination of AYP and are to be included in a school's improvement objectives. Since most people are not trained statisticians it is helpful to explore a few basics associated with interpreting data.
First, a few definitions:
The mean is the average of the scores in the population. Numerically, it equals the sum of the scores divided by the number of scores.
The median of a population is the point that divides the distribution of scores in half. Numerically, half of the scores in a population will have values that are equal to or larger than the median and half will have values that are equal to or smaller than the median.
The first task would be to look at the composition of the students taking this particular test. In doing so we need to identify our relevant sub groups. Under the NCLB Act they have been identified for us economically disadvantage, major racial and ethnic groups, students with disabilities and LEP students. So perhaps now our range of scores looks a bit different as a break them out into their sub groups.
Throughout the school year we have given a series of tests. Instead of just looking at one point in time we can track the results over the school year, trending the data overall and by each sub group. This will show if the results of one test may skew the results overall or for any sub group.
Looking beyond the initial sub groups you can drill down further into the data. Among our students with results in the bottom half of the class we might look at the factors such as prior course levels there were prerequisites to a current course or prior reading achievement levels etc.
In summary understanding data involves delving under the surface to see what the numbers really mean. Doing anything else short changes the students and is a recipe for failure.
| Additional Information |
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| Data-Driven Decision Making Study Relates Cautionary Tale of Misusing Data, Education Week, May 21, 2003 (Free Registration with Education Week Required.) Internet Glossary of Statistical Terms |
Sources:
"Cooking with Data" to Reduce Achievement Gaps, Craig Jerald, The Education Trust, enc Focus, Volume 10, No 1 2003, Eisenhower National Clearinghouse
Internet Glossary of Statistical Terms
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