Recency and primacy effect

The recency effect is the tendency to overweight recent information. The primacy effect is the tendency to overweight initial information. Both biases operate together, causing you to overvalue the first data point you see and the most recent data point you see, while undervaluing information in the middle. This creates temporal biases in judgment.

The primacy effect

The primacy effect is the disproportionate influence of initial information. When you first learn about a company, the initial information shapes your belief more than subsequent information of equal quality.

Example: You first learn that Company A has “good management.” Subsequent information that reveals management to be mediocre has less impact than it should. Your belief remains anchored to the initial “good management” anchor.

The primacy effect is related to anchoring bias: the first number you see anchors your estimate. The first impression you form anchors your belief.

The recency effect

The recency effect is the disproportionate influence of the most recent information. When evaluating a manager’s performance, recent returns weigh heavily. A manager who was mediocre for 10 years but strong for the last year is judged as strong, not mediocre.

Example: You are evaluating a stock. Over the past five years, it has underperformed. But in the last quarter, it has outperformed. The recency effect makes the recent outperformance loom larger than the five-year underperformance, biasing your judgment upward.

Recency vs. primacy: which dominates?

Whether recency or primacy dominates depends on context:

• Primacy dominates when information is presented all at once (you read a full biography), time has passed since the initial information, and cognitive load is high.
• Recency dominates when information is presented sequentially (you see quarterly earnings reports), the time since initial information is short, and cognitive load is low.

In investing, recency often dominates because information is sequential (quarterly earnings, daily prices) and recent information is vivid.

Primacy and primacy effect in manager evaluation

A fund manager has a strong first year, then underperforms for three years. Primacy effect makes investors reluctant to fire the manager: the initial strong year anchors the belief that the manager is good.

Yet, if the manager underperforms for three years and then has one strong year, recency effect makes the recent strength loom large. The investor becomes optimistic about future performance.

The same manager’s true quality (unchanged) is judged differently depending on which end of her track record is emphasized.

Recency, primacy, and narrative

A compelling narrative often combines both effects. The primacy effect makes you believe the initial narrative. The recency effect makes you sensitive to the latest news. A narrative stock initially performs well (primacy: you believe it), then underperforms (recency: recent underperformance dominates), then recovers (recency again: recent recovery dominates). Your beliefs ping-pong between optimism and pessimism.

Defenses against recency and primacy effects

• Use a longer history. Rather than the most recent year or the initial year, look at the full record. What is the average return, volatility, and consistency over the entire period?
• Weight information equally. If you are making a judgment based on multiple data points, weight them equally rather than allowing primacy and recency to distort.
• Separate the information from the presentation order. The order in which you encounter information should not affect your judgment. Ask: would my judgment change if I learned the information in a different order?
• Use a decision framework independent of order. A valuation model or a decision rule provides the same output regardless of information order.
• Track outcomes over long periods. When evaluating a manager or strategy, look at long-term results, not recent performance. The long term is less vulnerable to recency and primacy.

See also