By definition, standardized tests are administered and scored under clearly defined, uniform conditions. Most are commercially prepared for nationwide use, and they provide information about performance relative to others of the same age or grade.
To understand how standardized tests and their scores can be misused, it is critical to understand a little about the construction of such assessments. First of all, it’s important to note that in addition to providing a point of comparison, standardized assessments are designed to discriminate among students, which means there must be a spread of scores.
There are two kinds of questions that can ensure ‘spread’ exists. One is to design questions that are heavily influenced by socio-economic factors. (After all, socio-economic status is a nicely spread out distribution.) Students from middle class or upper class status are likely to do better on these types of questions because they are more likely to have encountered the content outside of school. (Yes, you read correctly, test items on standardized tests do not necessarily assess content taught in schools.)
The second type of question that can help ensure ‘spread’ exists are those that assess inherited academic aptitudes. If you are thinking to yourself, this is another example of testing something that is not necessarily supposed to be learned in school, you are right. In fact, some studies suggest that as much as 75 percent of the content assessed on standardized tests is not even supposed to be covered as a part of the school curriculum.
Finally, if you want substantial spread among the scores, items on the test will need to be answered incorrectly by about 50% of the test-takers. That’s right, you need about half of the students to miss questions so differences can be noted between and among students. It would seem obvious then, that questions which are designed to measure what I’ll refer to as ‘mainstream’ content are likely to be absent on such tests.
Now that you have a little better understanding of the role and construction of standardized tests, it should be obvious that such assessments should not be used to measure the effectiveness of a classroom teacher. After all, by design most of the questions on such test are not even designed to test content commonly taught in the classroom. Too many students would answer such question correctly, sabotaging the need for a spread of scores.
Commercially constructed standardized tests also have limited value as a formative assessment. It would be ludicrous to expect a test that measures very little of the content commonly covered at a grade level, to provide meaningful data to classroom teachers about mastery of the content.
Finally, when you consider that most of what such tests measure are inherent abilities, and experiences that students have outside of school, it should be obvious that they also have very little utility in measuring the quality of a given school. In reality if you want to judge the quality of instruction, a test should be designed to measure how well children were taught, not whether they’ve been fortunate enough to have rich life experiences outside of school.