Cambridge Brain Sciences percentile?

February 16, 2015 10:07 PM

How does CBS calculate percentiles? i.e. Looking at the distribution for the Odd One Out test, my top score seems to lie very comfortably in the top 5% or so range(it's not even close to the mean value of the (almost) normal distribution, while being very close to the right tail of the distribution); yet the percentile score is merely top 60%. What does this imply? Are the percentile scores representative of a smaller sample of better performers?
posted by red_alert_3 to Science & Nature (3 answers total)

Response by poster: Let me edit the question - the percentile score is not "top 60%"but rather top 40%(or better than 60%)
posted by red_alert_3 at 10:08 PM on February 16, 2015

Without seeing the graph your are looking at,
I would think that the 60% says that you have 60% of the highest score. Either the possible highest score, or the highest score a person has achieved.

This could still place you in the top 5% if the tail is very long.
posted by TheAdamist at 5:43 AM on February 17, 2015

The "performance rating" is very different to the percentile - although the wording implies they should tally. My first attempt I got a performance rating of 52% (which should mean top 48%) with a score of 14. When you take the IQ challange, a score of 14 on that test puts you in the top 13 percent. Looking at the graph, my new top score of 17 has 621 people scoring higher 610 scoring the same and about 62k scoring less - which would put a score of 17 in the top 1-2% - the "performance rating" for a score of 17 is given as 60%.

The only thing I can think of is that the performance rating is based on scores logged and the graph is based on people's high scores. So a score of 17 could only be in the top 40% of scores but in the top 1% of high scores
posted by missmagenta at 9:41 AM on February 17, 2015