This paper estimates the determinants of achievement in kenyan primaryrneducation by maa:'ing use of a Specially designed reading Comprehension test in EnglishrnJor Slandard Six Us A Proxy uf u(;'hievemeni. reading (;'umprehensiun is C:h(jsen un thernPresumption that the abilzty of the pupil to read and comprehend the language ofrninstruction is a sure w01 to better perjormance. the kenyan education system has arncycle of eight years and therefore, the level of comprehension of the pupils at standardrnsi.-.: Is A fair enough reflection of the quality of the entire education system.rnWe Make use of the data collected by the southern african consortium forrn}vfonitoring education quality (sacivfeq) under the national primary educationrnbaseline survey In 1998. the data Includes not only scores on the achievement testsrnstated above, but also detailed information on each child's household and the primaryrnschool he or she attends.In our analyses, we integrate the production fimction framework favored byrneconomists with the concerns of educators about pedagogical processes and those ofrnsocialists regarding school organization and management. we also correct for selectivityrnbiases induced by school choice between private and public schools bearing in mind thatrnparents in Kenya have considerable freedom in choosing which school their childrenrnattend. our results indicate that there is indeed a positive selection into the privaternschool. implying that given the opportunity, parent. are more willing to send theirrnchildren to private schools than public schools. our findings show that all the threerncomponents in an education system classified into: - both physical and pedagogicalrninputs; teaching process; and school organization and climate influence pupilrnachievemeni.rnbased on these results we conclude that beside heavy investments in educationrninvolving physical and pedagogical inputs alone, school reforms that concentrate on justrna few pedagogical practices could lead to substantial improvements in pupilrnachievements