GiveWell has made several big research-related grants, e.g. a $2M grant to IDinsight, part of which funds impact evaluations (which probably includes RCTs): http://www.givewell.org/charities/IDinsight/june-2016-grant
GiveWell has made several big research-related grants, e.g. a $2M grant to IDinsight, part of which funds impact evaluations (which probably includes RCTs): http://www.givewell.org/charities/IDinsight/june-2016-grant