## How the signs are computed

As discussed in more detail at Driver (Importance) Analysis#Score signs:

- The actual importance scores are computed in the normal way.
- The signs - that is, whether they scores are positive or negative - are from a multiple linear regression.

## Why showing negative signs is "wrong"

Both *Shapley* and *Kruskal* are conceived with the goal of computing whether or not a variable is "important", and neither framework has a concept of negative scores within it. As such, the implementation of these methods within Q is inconsistent with the frameworks that are being implemented, and if it is desired to exactly reproduce the Shapley and Kruskal methods, the negative signs should be ignored.

## Reason for the adjustment

*Shapley* and *Kruskal* implicitly assume that the user understands the true sign of the underlying variable. That is, they assume that the user knows which variables have a positive impact on the outcome variable and which have a negative impact. However, our experience in addressing user support queries is that many users do not have this understanding, and end up drawing the wrong conclusions from these methods as a result.

The following table shows an example. It shows that being `feminine` is perceived by men as having a negative effect on their liking of cola brands, whereas for women there is a positive effect. If this analysis is performed using the traditional formulation of *Shapley*, it is easily misread and gives, to quote a user, "the profound insight that men want their colas to be feminine" (i.e., because the traditional calculation shows a score of 20.9 for `Male` and 6.6 for `Female` respondents).

## Adjusting the signs

You can create a Custom Rule for modifying the signs so that they are all positive. See Making All Values in a Table Positive. This will not modify the significance tests.

Further reading: Key Driver Analysis Software

## Next

How to Run and Interpret Shapley Regression

Regression - Legacy Driver Analysis - Table of Shapley Importance ScoresRegression - Legacy Driver Analysis - Table of Kruskal Importance Scores