Keep criteria independent
Try to pick criteria that measure genuinely different things, so you are not weighting the same factor twice.
Add the options you are choosing between and the criteria that matter, weight each criterion, score every option, and see which one wins on a weighted total.
A decision matrix forces you to separate two things that often get tangled together: how important a factor is, and how well each option performs on that factor. By setting the weight once per criterion and then scoring every option consistently against it, the matrix produces a single ranked number instead of a vague gut feeling, while still leaving room for judgment about factors the matrix does not capture.
Try to pick criteria that measure genuinely different things, so you are not weighting the same factor twice.
Fill in every score before looking at the totals, so the ranking does not quietly influence how you rate each option.
Each score from 1 to 5 is multiplied by that criterion's weight, and the results are added up across all criteria for that option.
It divides the weighted total by the sum of all the weights, giving a normalized score out of 5 that is easier to compare across matrices with different total weights.
Yes, set each criterion's weight from 1 to 10 based on how important it is relative to the others.
Its scores are removed along with it. The remaining options and criteria, and their existing scores, are left untouched.
More handy tools from My Panda Toolbox.