Identifying the Halo/Horns Effect with a Performance Review System

Posted by Michelle • January 28, 2016 (Last modified May 25, 2023) • 3 min read

Most managers like to think they are fair as possible when completing employee performance reviews. Many even spend hours poring over every score on every competency. But despite the attention to detail, it’s common for successful employees to score high in every category and underperformers to receive low scores across the board. It’s caused by a rater bias known as the Halo/Horns Effect and utilizing a performance review system can help you eliminate it.

We all know that everyone, regardless of overall job success, has areas where they excel and areas where they can improve. In this article, we’ll outline exactly what the Halo/Horns Effect is, the problems it causes in the workplace, and how it can be avoided with a modern performance management process

What is the Halo/Horns Effect?

The Halo/Horns Effect is a cognitive bias that causes a person’s impression of someone to be overly influenced by a single personality quality, physical trait, or experience. It results in broad assumptions based on limited–and even completely irrelevant information. 

Psychologist Edward Thorndike first wrote about the Halo Effect in 1920. He performed a simple study in which he asked two high-ranking military officers to evaluate their soldiers on tangible qualities, such as neatness, and subjective qualities like intellect and leadership. The results of the study showed that if a soldier kept a neat appearance and living quarters their superiors believed they were smart and should be promoted.


In the context of a work environment, it’s easy to assume that well-dressed and articulate professionals excel at their jobs. However, just because someone is dressed for success and confident doesn’t necessarily mean they’re a successful employee. 

The opposite of the Halo Effect is the Horns Effect. The Horns Effect causes people to have a negative view of someone based on surface-level impressions. For example, people might assume someone who is out of shape lacks motivation. Or someone who doesn’t talk a lot in meetings can seem like they don’t care when they more than likely have an introverted personality. Racial, gender, and age biases are also examples of the Horns Effect. 

The Horns Effect can play out in less-obvious ways in the workplace. A negative perception of a manager can diminish the reputation of everyone on their team. Similarly, a new hire may struggle to meet expectations if they’re replacing someone who was known to excel.

How to prevent the Halo/Horns Effect

Unfortunately, even great managers can fall victim to the Halo/Horns Effect. There is so much going on in the workplace and it’s easy to get tunnel vision and omit crucial information when completing employee performance reviews.

A modern performance management process is designed to prevent rater biases by evaluating employees on the factors truly related to job success. Here are some tips for overcoming the Halo/Horns Effect.

  • Use goals to measure performanceEvaluate employees with SMART goals to ensure their performance review aligns with their tasks and responsibilities. 
  • Build effective performance review forms – Include descriptions to support review competencies and the options on the rating scale. 
  • Request managers take performance notes – Have managers document their direct reports’ performance throughout the review period so they have a record to consult when completing evaluations. 
  • Consider 360-degree feedbackCollect feedback from multiple raters so performance reviews include different perspectives.
  • Accept self-appraisals – Have employees review themselves so they can have a constructive conversation with their manager about their performance. 

The Rater Bias Report in Trakstar

Trakstar Performance Management comes with all the features you need to effectively evaluate employees. We also offer data-rich reports that help you optimize your performance management process, including the Rater Bias reports. 

The Rater Bias Report shows the range of scores raters gave to employees or teams. You can identify the managers who may be succumbing to either the Halo or Horns Effect and provide coaching that helps them provide fair and accurate evaluations.

Request a live demo of Trakstar today to build a better performance review system!

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