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 two quarters of 2015 compared to the previous two years (note 1).
Money moved by donors who have never given more than $5,000 in a year increased about 80% to $1.54 million. The total number of donors in the first two quarters increased 94% to about 6,000 (note 2).
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, we don’t think we can reliably predict our growth and think that our year-to-date total money moved provides relatively limited information about what our year-end money moved is likely to be (note 3). We therefore look at the data above as an indication of growth in our audience.
Growth in web traffic excluding Google AdWords increased about 40% in the first two quarters. 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 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 4, on how we count unique visitors).
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 two quarters” reported here are for February through July.
Note 2: Our measure of the total number of donors may overestimate the true number. We identify individual donors based on the reported name and email. Donors may not share all of this information or may update it (for example, using a different email), in which case, we may mistakenly treat a donation as if it was made by a new donor. We plan to investigate how large of an overstatement there may be and possibly adjust the total for our next annual metrics report.
Note 3: In total, GiveWell donors directed $5.56 million to our top charities in the first two quarters of this year, compared to $2.41 million that we had tracked in the first two quarters of 2014. For the reason described above, we don’t find this number to be particularly meaningful at this time of year. In the second quarter of 2015, a significant portion our money moved came from one large donation.
Note 4: 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.