# Vendor scorecard history

The History view compares the current ratings for each metric category with ratings from the previous 3 years or 4 quarters.

## Vendor scorecard: History

Ratings that have dropped are highlighted in red and display negative numbers. Ratings that have improved appear in green with positive numbers. Arrow icons beside the values in the Diff column indicate the trend of the current assessment against the previous assessment.
• 3 Years: To calculate the current ratings, the system averages the ratings from the trailing twelve month (TTM) period. The Diff column shows the discrepancy between the current ratings and the previous calendar year's ratings.
• 4 Quarters: Quarterly assessments compare the average rating for each category in the current quarter against the previous 4 quarters. The Diff column shows the discrepancy between the current ratings and the previous quarter's ratings. The column labels count backward, by quarter, from the current quarter. For example, if the current quarter is the 3rd quarter of 2013, then the previous quarters appear as 2nd [2013], 1st [2013], 4th [2012], and 3rd [2012]. The columns for all four of the previous quarters appear, whether or not there were any ratings for those quarters.

## Overall Rating

The Overall Rating is calculated as:
`(sum of normalized values in category result) / (number of assessment groups)`
In the following example, the calculation is
`(2.13 + 2.86 + 3.79 + 1.43 + 2.39 + 3.7) / 2 = 8.15`