A user-friendly instrument designed to collect and calculate indicators of effective inventory management. The IMAT guides the user through a process of collecting data on the physical and theoretical stock balance and the duration of stockouts for a set of up to 25 frequently-used products, calculating indicators, analyzing the results, and identifying strategies for improving record-keeping and stock management practices. The IMAT comes as a computerized spreadsheet in Excel and includes instructions, a data collection form, analysis guidelines, recommendations, and a graphical display of the indicator results.