Study protocol is important because it provides an integrity to the research by giving a clear path that defines and designs the study in order to avoid or reduce any other thing that can influence the result. the written protocol can also be a major asset in when it comes to study documentation, which is important for maximizing data quality and its also important for future updating and for secondary use.
an other importance of study protocol which is well designed and clear is that it protects the efficiency of the data and also the overall study objectives rather than individual data.