Understanding the Bell Curve in Appraisals: How Do You Use It for Increments?

Dear Friends,

Please find attached the sheet for the Bell curve.

A bell curve is a plot of the normal distribution of a given data set. The file which I have attached describes how you can create a chart of a bell curve in Microsoft Excel.

Hi Urvashi,

A bell curve is a plot of the normal distribution of a given data set. The file which I have attached describes how you can create a chart of a bell curve in Microsoft Excel.

Can anyone please tell me how to go about using this bell curve? I am still not clear with the usage of this curve in terms of increments and appraisals. :(

We intend to introduce some HR policies for use during annual increments and promotions of our employees.

In view of that, we want to share the HR policies that are being implemented in the automobile and dealership sectors.

Hi Smriti!

Please check with the person who had given you this Excel sheet. This is a classic example of misunderstanding the concepts and using them erroneously. What you call a bell curve is actually the "Normal Probability Curve" (since it is bell-shaped it is called a bell curve).

The Normal Probability Curve (NPC) is an ideal distribution plot of any measurable characteristic that is supposed to be normally distributed in the larger population. For example, if you measure the height of all people in the world, the distribution of the height will be close to the NPC (but it will never be exactly like that).

This is a misuse of NPC to project it as ideal in small samples that are conceptually "not normally distributed," e.g., if you plot the IQ of IITians, it would never be similar to the NPC as IITians are supposed to (and actually are) be on the higher side.

It is a misconception that the general big NPC is composed of several small NPCs. The graph here is a complete misrepresentation of the applicability of the concept.

Regards,

Vijai Pandey

Central Test: Leader in online psychometric testing

Hi Smriti,

I saw your bell curve xls but could not open it. Keep putting knowledgeable inputs for HR professionals. If I can help you in any way, let me know.

Poonam

Hi Smriti,

The Excel attachment really helps. I've been trying to find a simple Excel sheet to assist me with bell curve analysis for quite some time now, and this one's just what I needed.

Thanks a ton!

Dear Smriti, can you please help me in describing the fields, as I am doing the appraisal for the first time?

Ratings

- Recommended
- Ideal Curve

My rating scale is:
- 91-100
- 81-90
- 71-80
- 61-70
- <60

Should I put the above ratings in the "Rating" or "Recommended" category? How should I represent the percentages in the Ideal bell curve?

Thank you for your assistance.