Analytical PMAX Calculator
The Analytical PMAX Calculator is a web-based tool for examining the elasticity of demand for reinforcers. This calculator streamlines the determination of unit elasticity (i.e., slope = -1) using a simplified interface. Both Approximate and Analytic PMAX measures are provided.
Gilroy, S. P., Kaplan, B. A., Reed, D. D., Hantula, D. A., & Hursh, S. R. (In Press). An Exact Solution for Unit Elasticity in the Exponential Model of Demand. Experimental and Clinical Psychopharmacology.
This calculator uses several methods to evaluate models of operant demand (see Hursh & Silberberg, 2008) to determine a point where one log-unit increase in price corresponds to a one log-unit decrease in consumption, PMAX. This can be done using numerical approximations or through more computationally-exhaustive iterative methods, using the first order derivative.
To calculate PMAX here, you must paste the fitted Q0, alpha, and K parameters from the model of demand into the spreadsheet component (in their respective columns). Once entered, simply press the "Calculate" button to apply calculation the Analytical PMAX. Additionally, the Approxiate PMAX will also be outputted in the spreadsheet component, in its respective column.
Optionally, you may preview a sample of a exemplary data by pressing the "Load Sample Data" button and then pressing "Calculate". This will let you view the differences between the Approximate and Analytical PMAX.