Any programming should be based on valid data and core vocabulary is an essential data for curricula programmers and developers. Considering this fact OERP launched a national project for identification of "Iranian Primary School Students Core Vocabulary". In this project appropriate methods for estimating basic vocabulary were identified. Then through a massive field study, real, first hand data have been collected from 175 schools. These schools were sampled from rural and urban regions using systemic stratified cluster PPS sampling method. This sample included 46 girl schools, 64 mixed schools and 65 boy schools i.e. 20,000 students and 1,885 teachers in 875 classrooms in all provinces of Iran Several research tools were developed (check lists and questionnaires containing 1641 concrete nouns, 2700 verbs and adjectives in many semantic fields) for the purpose of this research and tests were conducted throughout the country in a tight time schedule. Many people were involved in this project such as 20 full time researchers (12 in phase one, 8 in phase 2), 40 test conductors 12 research staff, 4 teacher consultants, 10 part time staff, 1 accountant. In this paper the management of the project and some of its findings are reported.