Score by criterion across options, not by option across…
Score one criterion at a time across all options rather than one option at a time across all criteria, to force apples-to-apples comparison and reduce halo effects.
When This Fires
- Every time you're scoring options in a decision matrix (Use a weighted decision matrix when options exceed 3…)
- When you notice yourself thinking "this option just feels better overall" during scoring — that's the halo effect
- During group evaluations where one person's enthusiasm for an option might bias the group's scoring
- When you want the matrix to reveal new information rather than confirm existing impressions
Common Failure Mode
Row-first scoring feels more natural: "Let me evaluate Apartment A on all dimensions, then Apartment B." This feels thorough but produces inflated scores for whichever option makes the best first impression. You score Apartment A across all criteria while still under the spell of its best feature, then score Apartment B across all criteria while comparing everything to Apartment A's halo.
The Protocol
(1) After assigning weights (Assign criterion weights before scoring options — knowing…), score criterion by criterion, not option by option. (2) For criterion 1: evaluate all options on this criterion only. Which option is best on this dimension? Score them relative to each other. (3) Move to criterion 2. Forget how each option scored on criterion 1. Evaluate fresh on this new dimension. (4) Continue through all criteria. (5) Only after all criteria are scored → look at the totals. This is the first time you see each option's overall performance. (6) The column-first discipline feels slower, but it produces more accurate scores because each criterion is evaluated in a comparison context where the halo effect can't operate.