The next step is to determine the sources of data to be used. The researcher has to decide whether he has to collect primary data ror depend exclusively on secondary data. Sometimes the research study is based on both secondary and primary data.
When a study is to be based on secondary data whether partly or fully it is necessary to satisfy oneself that the data are quite suitable for the objectives spelt out by the study. It is also advisable to evaluate secondary data in detail to avoid possible sources of error. It is only when such secondary data are unavailable inadequate or unreliable that a researcher should decide on collecting fresh data.
Once the decision in favour of collection of primary data is taken one has to decide the mode of collection. The two methods available are observational methods and survey methods.