The results of this year's Stanford Achievement Tests are in.  Below is a summary of our understanding of what the test scores mean and how we use them.

Explaining the numbers

• Number of items - the number of test questions for each particular subject area.
• Raw score - the number of questions your student successfully completed for each of the subject areas.
• Scaled scored - ask a statistician, we don't use this result.
• National PR - S. National percentile rank - It compares your student's results to the national average of 100 students in the same grade. A 60 means that in that subject area, your child scored better than 60 of 100 students. A score of 35 means your child scored better than 35 of 100 students. The national average would be a 50.
• ACSI PR - S. ACSI is the Association of Christian Schools International. We test as part of their group. So this percentile score compares your student against the ACSI group instead of the national average. Your student's ACSI percentiles will be lower than the national average percentiles as the ACSI group scores better than the national averages. So this compares your child against 100 private Christian school students.
• Grade equivalent - The grade equivalent score is the most commonly misinterpreted score of these types of tests. Group administered achievement tests such as the SAT are composed of items with a limited range of difficulty for specific grade levels. In other words, third grade students are given content area questions specifically for third grade. If a third-grade student earns a grade equivalent of 6.5 on a test that is intended to be administered to Grade 3, it does not mean that the student will be successful on tasks associated with mid-sixth grade level. Rather, it means that the student got a high percentage of the items on a third-grade test correct - the same percentage of items correct that the average sixth-grade student would have. The student's score in this case is more a reflection of the student's accuracy than the grade level of task difficulty that this student can perform. PHS means post high school.
• Summary scores - Depending on the grade level, there will be a number of summary scores after the "content" subjects including: using information, thinking skills, basic battery and complete battery. The basic battery typically includes the core subjects of reading, math, language, spelling and science. The complete battery is the total of all the subjects.
• The bottom section, titled Content Clusters, gives the break down of results within by specific subject. The columns represent the number of questions the student completed correctly (RS), the number possible (NP), and the number answered by your student (NA). Thus the NA column will tell you if your student completed all the questions within a subject area.

Regarding the Otis-Lennon

For grade third, fifth, seventh and tenth grades only, our testing group also does the Otis-Lennon exam. This test is designed to measure the student's aptitude as opposed to their performance in the specific subject areas. The test results provide a percentile in the verbal and non-verbal areas for both their age and their grade level tested.

The AAC range column compares the performance of your student in a specific subject areas versus students with similar Otis-Lennon scores. Thus a "low" in the AAC range means the your student did not perform as well others with similar Otis-Lennon scores and a "high" means they scored better in the subject area than others with similar Otis-Lennon scores. We pay attention to “Low” ACC ranges as they indicate that our student, even if they are doing relatively well, could be doing better. As with the regular Stanford test scores, make sure the results fit with your knowledge of the student.

Some closing thoughts...  

• Don't put too much weight on one year's score. There can be any number of causes for a test score to be low or high on a particular test. We test every year to get a better picture of how they are doing (and it is good practice for them).
• Don't panic if their test scores are poor, esp. the first year they test and in the younger grade. Generally, the longer you homeschool, the better the scores.
• We try to prepare our students for the test and to make it something they look forward to, particularly the first year they test. We don't test before our students begin reading. We work through the practice tests with them. We buy juice and treats to make it a bit more fun. We don't require a lot of additional school work of them on testing week.
• Keep in mind that the national mean scores are not all that great. I believe I have read that the mean of the Lawrence public schools is significantly higher than 50.
• If you have older students who are doing well, you might consider testing them at a grade level higher.
• We used the SAT scores to get a good student discount on our student driver's insurance.
• We did the SAT tests through our students' 9th grade year. In 10th grade and beyond, we have switched to the college entrance exams (PSAT, ACT and SAT).

The above is my summary after years of seeking to interpret the results. I am not a professional. For more detailed information (and likely more accurate), check out a web site that Jeff recommended last year at http://harcourtassessment.com