AIDA

AIDA (Analysis of Interactive Decision Areas - Luckman, Operational Research Quarterly, 1967; Friend and Hickling, Planning Under Pressure: The Strategic Choice Approach by John Friend and Allen Hickling, 1987) is used when you have several inter-connected problems where the solution choices for one will affect the solution choices for another. You therefore need to evaluate the solutions as a group, but the number of theoretically possible group combinations may be large. AIDA identifies combinations that cannot coexist and can therefore be eliminated, hence substantially reducing the number of combinations you need to compare.

Assuming that you have already got a list of problems, and have identified possible solutions for each. Then:

1. Identify any problems that do not interact: Draw a matrix with the problem names on each axis (e.g. 5 problems need a 5x5 matrix); delete the diagonal and the bottom triangle, to leave one cell for each different problem pair. Mark each cell 'X' if any of the solutions in the pair of problems the cell represents cannot co-exist. Remove from AIDA any problems with a blank row in this matrix; these have no interactions, and you can work with them independently.

1. Identify incompatible pairs of solutions: Write each remaining problem with its solutions, on a large Post-it slip (e.g. 4 problems give four slips). Stick them on a large working area (e.g. a white-board). Go through each solution on each slip, checking it against every solution on all the other slips to identify any pairs of solutions that cannot coexist. Draw a 'bar-line' linking the two members of each such incompatible pair of solutions. Then all solutions in different problems that are not barred are free to be combined.
2. Create a solution tree: Create a tree-diagram that displays all compatible combinations of solution options. Remove any incompatible branches. The remaining solutions can now be compared against agreed criteria like any other set of solutions.