What it is
A pros/cons list is the simplest possible decision aid: two columns, one for arguments in favor of an option, one for arguments against. Its formal version is older than it looks — Benjamin Franklin described it in a 1772 letter to Joseph Priestley, calling it "Moral or Prudential Algebra." Franklin's twist was the part most people skip today: he assigned each item a rough weight, then canceled equally weighted pros and cons against each other until only the net imbalance remained.
The frame survives because it forces you to write your reasoning down. Decisions you can argue clearly on paper tend to be better than the ones you only argue in your head.
When to use it
Pros/cons is the right tool when a decision is roughly binary and you have time to think but not weeks. Reach for it when:
- Accepting or declining a single job offer
- Choosing whether to migrate to a new vendor or stay
- Deciding whether to relocate
- Saying yes or no to a non-trivial commitment (board seat, advisory role)
- Settling a small team disagreement where the trade-offs aren't yet on the table
It's the wrong tool when you have three or more meaningfully different options (use a Decision Matrix), or when uncertainty dominates (use a Decision Tree with expected values).
How to run it
- State the decision as a single yes/no question. "Should I take the role at Acme by next Friday?" beats "Career planning."
- Brainstorm pros and cons separately, in two passes. Don't write a pro and immediately rebut it with a con — that creates artificial symmetry.
- Aim for at least 8–10 items per side before you start evaluating. Quantity prevents premature closure.
- Weight every item on a 1–5 scale: 1 = minor, 5 = decisive on its own. Do this before you tally.
- Apply Franklin's method: cancel pros and cons of equal weight against each other. What remains is the honest residual.
- Check the residual against your gut. If they disagree, something is missing from the list — usually an unwritten value you're embarrassed to name. Write it down.
- Sleep on it before deciding. The residual rarely changes overnight, but your confidence in it should grow or evaporate.
Common pitfalls
The dominant failure mode is false symmetry: treating every entry as equally weighted, so the side with the longer list "wins." A single decisive con ("the role requires relocating away from my family") can outweigh ten minor pros. Weighting fixes this — without it, pros/cons is a popularity contest among your own arguments.
Second pitfall: listing what you already believe. If you've half-decided, you'll generate pros for the option you favor and cons for the alternative. Counter this by writing the list, then asking a trusted person to add three items to each column you missed.
Third: leaving out reversibility. A decision you can undo in three months should be weighted differently from one you're locked into for five years. Mark reversibility explicitly on items where it matters.
Fourth: omitting opportunity cost. The cons of choosing option A include the pros of option B that you'd be giving up. People consistently forget to write these down.
Variations
A natural next step is the Weighted Decision Matrix (also called Decision Matrix Analysis or Pugh Matrix). Instead of two columns, you list options across the top, criteria down the side, weight each criterion, and score each option per criterion. The matrix scales to more than two options and forces consistent criteria, but takes longer. Use pros/cons when you're choosing yes/no in an hour; use a weighted matrix when you're choosing among 3+ options over a few days. For decisions dominated by uncertainty rather than trade-offs, a Decision Tree with expected values is a better fit.