How Do We Calculate the Overall Score and Star Rating?
A one dimensional rating system, like the one Charity Navigator launched in 2002 to rate the Financial Health of charities, can be done with a simple addition of scores. But rating charities on two distinct components – (1) Financial Health + (2) Accountability and Transparency – in such a way that charities must excel in both areas in order to score well overall, requires a more complex calculation. In our two dimensional rating system the overall score is not a sum, but rather a measurement of the distance of two component scores from a perfect score of 100 and 100. The smaller the distance to the perfect score, the better the overall score. Mathematically, the formula we use to calculate the overall score is:
Although the calculation used to determine the overall score is complex, the rating table used for Financial Health, Accountability & Transparency and the Overall Rating is the same as illustrated below.
| Overall Rating: |
 |
 |
 |
 |
0 Stars | Donor Advisory |
| Overall Score: | ≥ 90 | 80 - 90 | 70 - 80 | 55 - 70 | < 55 | N/A |
| Overall Rating: | Overall Score: |
|
|
≥ 90 |
|
|
80 - 90 |
|
|
70 - 80 |
|
|
55 - 70 |
| 0 Stars | < 55 |
| Donor Advisory | N/A |
Visualizing the Math
To help understand the calculation for determining a charity’s overall score, we provide a visual tool on each charity’s rating page. The following graph is an example of what is shown on the ratings pages. In this example, the charity has a score of 88 in Financial Health (3-stars) and 77 in Accountability and Transparency (2-stars). Following the 88 score on the vertical scale and the 77 on the horizontal scale to where they meet, it is easy to see that the charity earns a 3-star overall rating.
You can also plug the charity’s two individual component scores – (1) Financial Health and (2) Accountability and Transparency – into the boxes below. This tool will perform the complex distance formula calculation for you so that you can easily obtain the charity’s overall score.
| 1 - Financial Health Score | 2 - A&T Score | Overall Score |
|---|---|---|
| 1 - Financial Health Score | |
| 2 - A&T Score | |
| Overall Score |
