In most countries, a standardized national examination system is in place. At the end of each education cycle, e.g. end of grade 3 and 5/ 6, students sit a national exam. The indicator should be measured for these grade(s). This indicator is based on secondary data analysis.
At the start of the project, find out which institution is responsible for the exam test evaluations (e.g. local/ district level education department, Ministry of Education, schools, external bodies, etc.). Enquire about the locally acceptable performance standards for the tests to decide on the desired score (%). If such a standard is not available, then base your benchmark on the past year's test scores (unless recommended otherwise).
Try to obtain the previous year’s exam results, ideally disaggregated by class, gender and subject in target schools, directly from the "test evaluating body". Calculate the number and proportion of students who performed at or above the given score.
At the end of the project (and if possible also every year for the midterm), follow exactly the same procedure. Get the disaggregated student exam results (of the selected grade). Calculate the number and proportion of students who performed at or above the given score.