Base line study or Base line Survey is necessary to see the changes of a development project before and after its implementation. A change in the situation overtime is central to the implementation of any development project. The implementation status of a project in terms at a certain point in time is only comparable when the Base line data is in place. Base line information may comprise both quantitative as well as qualitative information regarding the concerned project. Justifiably Impact evaluation would be able to estimate the proportion or the extend of changes occurred as a result of project interventions following the comparison with the available Base line information. The same will occur in case of Benefit monitoring or Benefit assessment within the overall Monitoring and Evaluation Frame-work.
The design and formulation of Base line Study presupposes a very appropriate horizontal and vertical sampling of respondents across the study area. Faulty or erroneous information in the Base line study gives wrong and misleading message to the impact evaluation team in terms of decision making in course of doing Benefit assessment. On the other hand, good Base line Study will assist to contribute tremendously towards formulation of realistic magnitude of changes to be attached to specific indicators in course of project implementation under the umbrella of project cycle management. At this stage monitoring and evaluation will be able to play its due and realistic roles.