The two primary activities in the pre-analysis processing phase are the estimation of test parameters and the conversion of test measurements into normalized response data. The response data from a slug test typically consist of depth to water measurements obtained with an electric tape or, most commonly, measurements of the pressure exerted by the overlying column of water obtained with a transducer. The end product of the pre-analysis processing is a record of the normalized deviation of head from static versus the time since the test began. The lack of pre- and post-test monitoring data can introduce uncertainty into the estimate of the static pressure head. The form of the transducer data will depend on the data-acquisition device to which the transducer is connected. The appropriateness of the approach can be assessed using a plot of the logarithm of the response data versus time.