The Bell Curve Fallacy

12/18/05 3:36 PM 0 Comments

Everyone one has heard of the Bell Curve principle. Basically the Bell Curve theory states that in any given population, abilities will be distributed in a manner that forms a curved shape on a plot consisting of standard deviations. This theory relies on mathematical principles used in empirical research methods applied to case studies and standardized tests. When a study or a gathering contains a truly representational sampling of the population, this theory holds water.

HOWEVER, there are many idiots that believe this theory applies to any sampling of a population, representational or not. Thanks to these types of morons, you will find Bell Curves being applied in circumstances, such as educational settings, where the population's sample is neither large enough nor diverse enough to be considered truly representational of the population as a whole. Some of you now out of the educational setting may be asking, "Why should I care?"

Well, everyone should care about this principle because it is now trickling into business practices. There the Bell Curve takes on more dangerous connotations. Business are now using the same A-F scale as educational institutions when assessing employee performance, except to a greater extreme. In businesses, a "C" grade constitutes an employee meeting all expectations set by their employer. Anything below this results in a "D" or "F" grade meaning that the employee has not met performance expectations. In order to exceed expectations, an employee must not only complete everything set before them but must exceed the expectations in such a way that their employer cannot deny their value to the company. The only way this can be obtained is by working extra long hours and devoting your entire life to your job. Luckily this standard is only being used in major manufacturing corporations at this point. If it was being used in retail or other fields, the public might not be able to purchase groceries, etc. The biggest fallout of this phenomena is that employees who work hard at companies are not getting adequate raises beyond cost of living increases. This places organizational theory back into the times of Taylor's model which was developed in the early 1900's. What this means is that rather than improving organizational methods, American businesses are regressing to less productive models.

This theory as it applies to the classroom is also doing similar damages to students forced into this curve.

I have news for corporations and educators regarding this theory: Your sample of the population is not representative. As career requirements and educational levels progress, people at the "C" level or below have already been eliminated from your sample. If the employee cannot handle the job requirements, you are not going to hire them; therefore, you have already disintegrated what the Bell Curve relies on. Employee's performance should not be based on exceeding expectations when those expectations could possibly be set by an unreasonable manager. The quality and timeliness of work, rather than the impressiveness, should be what is measured. For educators, assignments have a possible numbers of points that can be obtained, and grades should be based on how many points are obtained. Any assignments that do not have a clear rubric identifying the points possible and how they can be achieved should not be given.

Anyway, anyone investing in the Bell Curve where the stakes are as high as a person's future career or means of living needs to take an Empirical Research Methods class. Then you will understand what a representational sampling is, and thus understand when methods based on this kind of sampling should be applied.


“If you don’t turn your life into a story, you just become a part of someone else’s story.” – The Amazing Maurice and His Educated Rodents