The Gates Foundation received lower than average ratings in many aspects of its relations with grantees, CEO Jeff Raikes disclosed in a letter today.

The results were disclosed following a survey of more than 1,500 non-profits who received grants from the Gates Foundation over the last year. Raikes said the foundation worked with the Center for Effective Philanthropy to measure the perceptions of its grantees.

"They say we are inconsistent in our communications, and often unresponsive," he wrote.

The grantee perception report is a standard benchmark in philanthropy and has been used by nearly 200 funding organizations.

While non-profits said the foundation is having a positive effect on knowledge, policy, and practice, "we received lower than typical ratings on many other aspects of the grantee experience," Raikes said.

Staff turnover at the foundation created more work for the non-profits. The foundation was also criticized for not communicating its goals and strategies or its decision-making and grant making processes clearly.

Raikes vowed to make changes, including explaining how the grant proposal and approval process works, giving grantees a point of contact and allowing all of its partners to ask Gates Foundation executives questions.