The CTI drift measurement code ATC-140 specifies that isokinetic measurements be employed for cooling tower drift emissions measurements. The sensitive paper techniques, an alternative method also referenced by the test code, provide additional information not supplied by the Isokinetic test procedure. There have been few occasions; over the years when both the Sensitive paper and HGBIK drift measurement techniques have been employed at the same location. This has allowed only periodic comparisons of the results of the two techniques. Both methods were employed at the same location during a recent test program. The results create an opportunity to revisit some of the traditionally held views of the expected relationships between the results of the two techniques. This paper compares the data supplied by each method as well as the drift rates measured by each. This paper also addresses issues relevant to the determination of the rate of the efflux from cooling towers of chemicals entrained in the drift.