In addition to evaluations of other charities, GiveWell publishes substantial evaluation of itself, from the quality of its research to its impact on donations. We publish quarterly updates regarding two key metrics: (a) donations to top charities and (b) web traffic.

The tables and chart below present basic information about our growth in money moved and web traffic in the first quarter of 2015 compared to the last two years (note 1).

Money moved by donors who have never given more than $5,000 in a year increased 78% to about $760,000. The total number of donors in the first quarter increased to about 3,400. This was up 70% compared to last year, roughly consistent with the last year’s growth.

Most of our money moved is donated near the end of the year (we tracked about 70% of the total in the fourth quarter each of the last two years) and is driven by a relatively small number of large donors. Because of this, our year-to-date total money moved provides relatively limited information, and we don’t think we can reliably predict our year-end money moved (note 2). Mid-year we primarily use data on donations from smaller donors, rather than total money moved, to give a rough indication of how our influence on donations is growing.

Growth in web traffic excluding Google AdWords increased moderately in the first quarter. Last year, we saw a drop in total web traffic because we removed ads on searches that we determined were not driving high quality traffic to our site (i.e. searches with very high bounce rates and very low pages per visit).

GiveWell’s website receives elevated web traffic during “giving season” around December of each year. To adjust for this and emphasize the trend, the chart below shows the rolling sum of unique visitors over the previous twelve months, starting in December 2009 (the first period for which we have 12 months of reliable data due to an issue tracking visits in 2008).

We use web analytics data from two sources: Clicky and Google Analytics (except for those months for which we only have reliable data from one source). The data on visitors to our website differs between the two sources. We do not know the cause of discrepancy (though a volunteer with a relevant technical background looked at the data for us to try to find the cause; he didn’t find any obvious problems with the data). (Note on how we count unique visitors.)

The raw data we used to generate the chart and table above (as well as notes on the issues we’ve had and adjustments we’ve made) is in this spreadsheet.

Note 1: Since our 2012 annual metrics report we have shifted to a reporting year that starts on February 1, rather than January 1, in order to better capture year-on-year growth in the peak giving months of December and January. Therefore, metrics for the “first quarter” reported here are for February through April.

Note 3: We count unique visitors over a period as the sum of monthly unique visitors. In other words, if the same person visits the site multiple times in a calendar month, they are counted once. If they visit in multiple months, they are counted once per month. Google Analytics provides ‘unique visitors by traffic source’ while Clicky provides only ‘visitors by traffic source.’ For that reason, we primarily use Google Analytics data in the calculations to exclude AdWords visitors.