Checking raw data is a vital part of developing confidence in your data source. As explained in Working and Master Table Overview, raw data must flow through Working tables and be validated before they can be considered QA qualified to be transferred into a Master table.
Data validation ideally would consist of examination of raw data to be sure it is:
within analytical limits
reasonable considering historic observations
consistent with measurements of other parameters
(e.g., it might be unreasonable to have very low DO and BOD)
consistent with measurements at other locations
correctly entered from raw data sheets
These validations would probably need to be done by an experienced environmental or water resources professional.
On the other hand, minimal effort might be required to validate a data set. For example if model output data are being added to a Master table, a quick spot check of Working table values against a model output printout might suffice. It is the Project Manager’s responsibility to define what constitutes data validation.