Third Order Effect

A third-order effect is a consequence of a consequence of a consequence. It is the third link in a causal chain, reached by asking “and then what?” one step further than second-order thinking.

The idea

First-order effects are the immediate, obvious result of a decision. Second-order effects are what those results then cause. Third-order effects go one step further. They are delayed and easy to miss, because two intervening steps separate them from the original decision. Predictions get less certain the further out they go. The aim is to catch consequences a shallower analysis would miss, especially ones that offset or reverse the decision’s apparent benefit.

When to use it

• High-stakes or hard-to-reverse decisions, where a delayed consequence is costly.
• Policy, product, or organizational changes that ripple through an interconnected system.
• Whenever a decision’s first-order effect looks obviously good. A later-order downside is easiest to miss then.

How to apply it

1. State the decision and its immediate, first-order effect.
2. Ask “and then what happens?” to get the second-order effect.
3. Ask it again to reach the third order, noting where confidence starts to drop.
4. Weigh the first-order, second-order, and third-order effects together.

Watch out for

• Confidence drops with each order out. Treat third-order predictions as scenarios to watch for. Later orders are too uncertain to count as forecasts.
• It’s easy to stop right after the first favorable-looking effect; keep asking “and then what?”
• Chains branch rather than stay linear, so one decision may have several distinct third-order effects.

Related models

• Second-Order Effect. The preceding link in the same causal chain.
• Probabilistic Thinking. For weighing the declining certainty of later-order effects.
• Decision Making on Short, Medium, and Long Term. Later-order effects tend to surface over longer horizons.

Sources

Tracing decisions through multiple orders of consequence is discussed by investor Howard Marks in his Oaktree memos on “second-level thinking,” and popularized as first-, second-, and third-order thinking by Shane Parrish’s Farnam Street.