The members of the research program treated the most important methodological issues in the social science research in the period 1999 to 2003. They presented very successfully their research results to the international scientific world by publishing papers in the best scientific journals in the research fields, by acting as members of the editorial boards of such journals (e.g., Journal of Mathematical Sociology, Social Networks, Journal of Classification), by invitations to present plenary or invited talks at the international scientific conferences and to act as members in the program committees of such conferences. Members of the research program themselves organized several international scientific conferences in the field of methodology and statistics and they edit the series Metodološki zvezki in which most of the issues are published in English. The most distinguished research results are obtained in the following topics: - reliability and validity of measurement of complete and egocentered networks - development of blockmodels, to which the most interest is given in the field of social network analysis, - the development of algorithms and the program Pajek for the analysis of very large networks; the program Pajek is very popular among researchers of different scientific fields in the world, - modeling of nonresponse in survey research: by the proposed models it is possible to analyze the factors which affect the rate of nonresponse, with them it is possible to predict the nonresponse and to correct the errors because of the nonresponse after the data collection. The results of this research is very important also for the official statistics. - treatment of the methodological problems when studying the information society, - adaptation and development of mathematical models in the social sciences.