Update: SilkRoad says there are errors in the report it published Thursday on which the post below is based. The most significant appears to be charts on pages 8, 11, and 15 and in the infographic on the SilkRoad blog showing some sources produced more hires than they did interviews. A company spokesman said in an email: “The issue concerning the numbers on Craigslist was an error and has been changed.  In regards to the information on page 15, that chart only represents the percentage of interviews and hires as a percentage of all external sources and does not take into account internal or offline sources.” Additionally, “There were no sources in our findings with a larger number of hires over interviews.  The issue with the image on page 11 is with the chart and Craigslist.”Note that as of this update, it does not appear the updates to the charts have been made.

Referrals and the company career site are the two leading sources for new workers hired by the 1,054 companies participating in SilkRoad’s just released study of recruitment marketing effectiveness.

Between them, they produced 40% of the more than 150,000 hires the companies made in 2012.

This is the second year the HR software provider has compiled ATS data from its customers to report on their source of hire. This year, the company included interviews as a measure of effectiveness.

The data set came from companies as small as 100 employees and some larger than 10,000; 60% had under 2,000 employees, 30% fall between 2,000 and 10,000, and the remaining 10% are larger. A company spokesman said the employers represent “the entire scale. We have lots of technology, healthcare, higher education and several other strong verticals.”