Dumb math question [calculating an index]

[mv0087]

How would I structure a formula to calculate an index based off a number that can be negative or positive?

 

[shg]

For example, ...?

 

[mv0087]

For example, ...?

So if target = 3% and actual is 3% the index is 100.

If target = -3.29% and actual is 2.05% the index is 162.

If target = -2.86% and actual is -.023% the index is 99.

 

[mv0087]

Sorry that math is off...my brian is fried ATM.

 

[shg]

Nor sure I follow that.

      --A--- ---B--- ---C---
  1   Target Actual   Index 
  2       3%      3%     100
  3   -3.29%   2.05%   160.5
  4   -2.86% -0.023% 12434.8

C2 and down is =100*ABS(A2/B2)

 

[mv0087]

I guess that is what I am not following, how can a variance of 5.34 have a lower index than a variance of <3?

 

[shg]

Pardon??

 

[sdruley]

Pardon??

Resonding to: "I guess that is what I am not following, how can a variance of 5.34 have a lower index than a variance of <3?"

Mr. mv0087,

shg has already provided an excellent example of an index as well as the algorithm behind it.

Be careful when trying to compare one variance system over another when the targets are different. If all of the targets were the same then you could compare or if the underlying algorithm was based on the standard deviation then you could compare even if the targets were different.