In 2015-2017 Twaweza East Africa implemented KiuFunza II, a randomized performance pay trial in the early grades of public primary schools in Tanzania. This trial is part of an experimental program to improve learning introduced by Twaweza in collaboration with J-PAL/IPA. KiuFunza implemented two different teacher performance pay systems. The first system is called Stadi (levels) and rewards teachers based on the number of students that reach specific proficiency levels. The second is called Mashindano (gains) and rewards teachers based on their students’ test score ranking relative to children with the same starting level. The performance pay learning impact was studied in a nationally representative sample of 180 schools (60 schools randomly selected into each of the two incentive pay programs, and 60 control schools). The evaluation finds that both teacher performance pay systems improved student test scores. The simpler “levels” system was at least as effective in raising student learning as the more complex “gains” system. Furthermore, the levels scheme had a more equitable distribution of benefits, improving learning across all initial ability levels.