The Differential Sticking Tester was designed to determine how likely a given drilling fluid will be to produce a “stuck pipe” situation and how effective a given drilling fluid treatment or application of spotting fluid in any given drilling fluid would be in reducing this tendency. This measurement is called the “Stuck Tendency Coefficient”. It takes into account both the stickiness and the cake building capability of the drilling fluid. The “Stuck Tendency Coefficient” is determined by the Timed Filtrate Test.