The Impact of Human Bias on Analysts' Forecasting Abilities

Jan 24 / Geoff Robinson
Forecasting is essential for analysts, providing valuable insights for decision-making. However, human bias can significantly influence analysts' ability to produce accurate forecasts. In this blog post, we will explore how human bias can affect analysts' forecasting and present actual quotes and statistics to support our arguments.
People who are experts in a domain are often not better forecasters than those with minimal knowledge"
Daniel Kahneman
Thinking, Fast and Slow
Confirmation Bias: Confirmation bias is a cognitive bias where individuals seek out and interpret information confirming their pre-existing beliefs or hypotheses while ignoring contradictory evidence. In forecasting, this bias can lead analysts to selectively focus on data that supports their initial assumptions, disregarding contrary information. Nobel laureate Daniel Kahneman explains, "People who are experts in a domain are often not better forecasters than those with minimal knowledge" [1]. This bias can undermine the objectivity and accuracy of forecasts.

Bias: Overconfidence bias refers to the tendency for individuals to overestimate their abilities or the accuracy of their forecasts. This bias can harm forecasting accuracy as analysts may be excessively optimistic about their predictions. A Duke University's Fuqua School of Business study found that analysts are generally overconfident in their earnings forecasts, leading to significant forecast errors [2]. The study revealed that analysts' forecasts missed the mark more frequently than predicted, indicating the overconfidence bias's impact.

Anchoring Bias: Anchoring bias occurs when individuals rely heavily on an initial piece of information when making subsequent judgments or estimates. Analysts can be influenced by the first data point or anchor, which may lead to biased forecasts. For example, a study published in the Journal of Forecasting found that analysts tend to anchor their earnings forecasts to the company's prior-year earnings, resulting in a slow adjustment to new information [3]. This bias can impede accurate forecasting and responsiveness to changing circumstances.

Availability Bias: Availability bias refers to relying on readily available information when making judgments or decisions. Analysts may be influenced by recent events or easily accessible data, leading to biased forecasts. Research by Stanford University Professor Nicholas Bloom highlights the impact of availability bias, stating, "A lot of economic forecasters spend their time analyzing the most recent data, and that biases their forecasts towards whatever just happened" [4]. This bias can hinder analysts' ability to consider various factors and variables in their forecasts.

The idea of rationality, of unbiased, scientific forecasting, simply doesn't exist"
Daniel Kahneman
Thinking, Fast and Slow


Human bias poses a significant challenge to analysts' forecasting abilities. Confirmation bias, overconfidence bias, anchoring bias, and availability bias can distort their judgment, leading to inaccurate predictions.

As Nobel laureate Daniel Kahneman aptly summarized, "The idea of rationality, of unbiased, scientific forecasting, simply doesn't exist" [1]. Analysts must be aware of these biases, continuously challenge their assumptions, and employ rigorous analytical techniques to mitigate the impact of bias and improve forecasting accuracy.

By acknowledging and addressing these biases, analysts can strive for greater objectivity and develop more reliable forecasts better aligned with the reality of the markets and business environments they analyze.

[1] Daniel Kahneman, "Thinking, Fast and Slow"
[2] Duke University's Fuqua School of Business, "Are Analysts Overconfident? Evidence from Short Sellers"
[3] Journal of Forecasting, "The Anchoring-and-Adjustment Bias in Earnings Forecasts"
[4] Stanford University, "The Bias Against Economic Forecasting"