State what all the problems are, their relative importance, and their root causes. Then chose (a) problem(s) to solve.

You will probably do the following:

1) Brainstorm for all the problems with the process, then use a Fishbone Diagram or similar to organize the problems.

2) Choose (a) problem(s) to solve using tools like Pareto Diagram, Check sheets, etc. and state why you chose this problem(s). This may well more include data collection.

3) Collect detailed data on the problem using tools like Control Charts, Histograms, Pareto Diagrams, etc. to find its(their) root causes.