Issa, F. O. (2015). Methods of data collection in agricultural extension research. In Madukwe, M.C. (ed) A Guide to Research in Agricultural Extesion, 3 rd Edition, AESON Publication, Ilorin. Pp 55 – 75. 55 Methods of Data Collection in Agricultural Extension Research __________________________________ Issa, Fadlullah Olayiwola Introduction Data can be defined as the body of factual information which can be qualitative or quantitative. Data are often in the form of facts or figures obtained from experiments or surveys and used as a basis for making calculations or drawing conclusions (Alamu and Olukosi, 2010). Often, statistics are used to denote data. Statistics are a collection, analysis and interpretation of numerical data. Data collection for any research work is very important and hence must be well planned in order to ensure adequate success. The adequacy or inadequacy of the data collected will determine the success or failure of such study. An important consideration in data collection is the relevance, timeliness as well as the appropriateness of the data. Systematic development of the questionnaire for data collection is important to reduce measurement errors--questionnaire content, questionnaire design and format and respondent. Well-crafted conceptualization of the content and transformation of the content into questions is essential to minimize measurement error. Careful attention to detail and understanding of the process involved in developing a questionnaire are of immense value to extension researchers. Not following appropriate and systematic procedures in questionnaire development, testing, and evaluation may undermine the quality and utilization of data (Esposito, 2002). Anyone involved in educational and evaluation research, must, at a minimum, follow careful steps to develop a valid and reliable instrument for data collection in order to enhance the quality of research. Qualitative Versus Quantitative data collection Olawoye (2004) asserts that quantitative method of data collection has a longer history of development and use in social science than qualitative method but it (quantitative method) is not sufficient for facilitating sustainable development intervention in rural and agricultural development. According to Farinde (2004), quantitative data are collected through quantitative research methods e.g. surveys, observation, content and document analyses. Both qualitative and quantitative data can be generated in agricultural extension research either singly or combined. Patton (1980) states that “qualitative modes of understanding the world are rooted in philosophical and epistemological traditions that require explication in order to establish a context for making decisions about the usefulness, credibility, validity, and appropriateness of various qualitative evaluation strategies”. Jacob (1987, and 1988) has categorized the use of qualitative inquiry into six separate domains based upon historical traditions. These six domains attempt to: (1) understand behavior in CHAPTER 6