To understand the 4/5ths rule you have to first know about the Uniform Guidelines on Employee Selection Procedures. This is because the 4/5ths rule comes from them. It can be unwieldy to write or say “the Uniform Guidelines on Employee Selection Procedures” every time you want to refer to it so it is often simply called the Uniform Guidelines, the Guidelines, or the UGESP.

Background on the Uniform Guidelines

The Uniform Guidelines were first published in 1978 by four U.S. federal government agencies. It is such an important document that anyone who works in the area of human resources should have an understanding of it.

It is helpful to have a little bit of historical background information on the Guidelines. When Congress enacted the Civil Rights Act of 1964 federal agencies became responsible for implementing, monitoring, and enforcing compliance with the Act. Because of this many different government agencies independently published guidelines on employee selection. Clearly, having many different sets of guidelines was difficult to follow and confusing. As a result, four of federal agencies that were heavily involved with the act got together and created a set of “uniform guidelines” that they could all agree upon.

Four Agencies that Wrote the Uniform Guidelines for Employee Selection Procedures
  • Equal Employment Opportunities Commission (EEOC)
  • Department of Justice
  • Department of Labor
  • Civil Service Commission (now the Office of Personnel Management)

The Uniform Guidelines where first published in 1978. The very next year, in 1979, these same four agencies issued a set of 93 questions and answers regarding their Uniform Guidelines.

It is interesting to note, and somewhat funny, that the Uniform Guidelines is 16,816 words long and the questions and answers is 17,420 words long. Thus, the right after they published the Uniform Guidelines they had to publish an even longer document to clarify the document that was meant to clarify how to stay on the right side of the law.

An important point to make right up front about the Uniform Guidelines is that they are not law. They are not even regulations. Because of this they of course do not carry the rule of law. Rather, as their name implies, they are merely guidelines. They are intended to assist employers, labor organizations, employment agencies, and licensing and certification boards to comply with the requirements of federal law. While they are not law, nor regulations, the Supreme Court established in 1971, in the landmark Griggs v. Duke Power case, that the EEOC guidelines should be given “great deference” by the courts.

The astute reader, though, will recognize that in 1971 the Uniform Guidelines did not even exist. This was the time period when different government agencies had their own unique guidelines. When the EEOC accepted the Uniform Guidelines in 1978 they became their guidelines by default they assumed the “great deference” already established by the Supreme Court. Subsequent court decisions have affirmed this and so the Uniform Guidelines are still given great deference.

What is an Employee Selection Procedure?

Before you try to apply the Uniform Guidelines you need to first have an understanding of what constitutes an “employee selection procedure.” There is regularly confusion about this. As you will see, the phrase is interpreted more broadly than you might expect. Section 2.B of the Guidelines states the following:

B. Employment decisions.
These guidelines apply to tests and other selection procedures which are used as a basis for any employment decision. Employment decisions include but are not limited to hiring, promotion, demotion, membership (for example, in a labor organization), referral, retention, and licensing and certification, to the extent that licensing and certification may be covered by Federal equal employment opportunity law. Other selection decisions, such as selection for training or transfer, may also be considered employment decisions if they lead to any of the decisions listed above.

Many people mistakenly believe that the guidelines only apply to written tests. Even a casual reading of Section 2.B shows this is not the case. Under the definition above, many different types of personnel actions taken by organizations can be construed as an employment decision and are therefore subject to the Uniform Guidelines.

Adverse Impact and the 3/4ths Rule

Next we need to have an understanding of how the Uniform Guidelines define and identify discrimination. There are different forms of discrimination. The type we are concerned with here is adverse impact and it comes from the already mentioned Griggs v. Duke Power decision. In this case the Supreme Court focused on the fact that a minority group was disqualified by a selection procedure “at a substantially higher rate” than the majority group. Unfortunately, the court did not specify what a “substantially higher” disqualification rate meant.

If we had a clear and unambiguous standard to use organizations would know when to take action. Without a standard there was much ambiguity and it was difficult for organizations to use the Court’s Griggs decision for guidance.

Fortunately, since the Uniform Guidelines were written after the Griggs decision they addressed this problem by defining what “substantially” meant. According to the Uniform Guidelines in Section 4.D:

A selection rate for any race, sex, or ethnic group which is less than four-fifths (4/5) (or eighty percent) of the rate for the group with the highest rate will generally be regarded by the Federal enforcement agencies as evidence of adverse impact, while a greater than four-fifths rate will generally not be regarded by Federal enforcement agencies as evidence of adverse impact.

If you are confused by this definition don’t worry. Many people where. The questions and answers that were published following year included 22 questions dealing just with the concept of adverse impact.

4/5ths Rule Example 1

Sometimes definitions get in the way of understanding. It can be easier to understand a concept by working an example so here is one taken the questions and answers that demonstrate how adverse impact and the 4/5ths rule works. The questions and answers present a four step process.

  1. Calculate the rate of selection for each group (divide the number of persons selected from a group by the number of applicants from that group).
  2. Observe which group has the highest selection rate.
  3. Calculate the impact ratios, by comparing the selection rate for each group with that of the highest group (divide the selection rate for a group by the selection rate for the highest group).
  4. Observe whether the selection rate for any group is substantially less (i.e., usually less than 4/5ths or 80%) than the selection rate for the highest group. If it is, adverse impact is indicated in most circumstances.

Suppose an employer gave a selection test to 120 applicants. Of these, 80 were White and 40 were Black. Based on test results, 48 of the White applicants were hired, and 12 of the Black applicants where hired. This means that 60% (48 out of 80) of the White applicants were hired. Another way of saying the same thing is that the selection ratio of White applicants was .60. For the Black applicants, 12 out of 40, or 30% were hired. Therefore, the section ratio of Black applicants was .30.

If 30% of the Black applicants were hired and 60% of the White applicants were hired, intuitively you can see that the selection ratio for Black applicants (.30) is only one half of the selection ratio of the White applicants (.60). Mathematically, we would calculate this by dividing the smaller selection ratio (.30) by the larger ratio (.60). When we make this calculation we see that .30/.60 = .50. This tells us that selection rate for Black applicants was only 50% of the rate for White applicants. Clearly, Black applicants were hired at much lower rate than White applicants.

Under the Uniform Guidelines, adverse impact is indicated when one group is selected at a rate of less than 80% (or 4/5th) of the rate of another group. In our example, the Black applicants were selected at 50% of the rate for White applicants. Because 50% is less than the required 80%, the selection procedure is said to have resulted in adverse impact against Black applicants.

All of this is shown in the table below.



Selection Ratio/Percent Hired

80 White


48/80 = .60 or 60%

40 Black


12/40 = .30 or 30%


Lowest selection rate/Highest selection rate = .30/.60 = .50 or 50%


50% < 80% therefore there is adverse impact.

In order for there to have been no adverse impact, the selection ratio for Black applicants would have had to have been at least 80% (4/5ths) of the selection ratio for White applicants. In this example, it would be equal to (.80 * .60) or .48. In words, 48% of the Black applicants would have had to been hired for there to have been no adverse impact.

4/5ths Rule Example 2

For this next example we won’t worry about putting racial labels on the groups. That’s because it doesn’t matter what the group is. When calculating the overall selection ratio you do not always place the majority group on the bottom part of the fraction. While it is assumed that the majority group will often have the greatest selection ratio this does not have to be the case. The questions and answers clearly state that if the ratio for “any” group is less than 4/5ths of ratio for “the group with the highest selection rate” then the 4/5ths rule has been violated.

In this example, we have three groups.




Selection Ratio




50/100 = .50




15/45 = .33




15/31 = .48

With three groups we have to compute three different “impact” ratios.

1. Compare Group A and Group B
When comparing these two groups we first noticed that Group A had the highest selection ratio and we put it on the bottom. Group B then goes on the top of the fraction. We do the same for the two other impact ratios.

4 5thsRuleImage1

2. Compare Group A and Group C

4 5thsRuleImage2

3. Compare Group B and Group C

4 5thsRuleImage3

After doing the computations we see that Group B was hired at a sustainably lower rate than Group A. Group B was also hired at a substantially lower rate than Group C. Both calculations involving Group B were lower than 4/5ths or .80. This is an indication of adverse impact.

Why 4/5ths?

There is absolutely nothing special 4/5ths. In fact, its use seems to be based on the “Goldilocks principle.” Barrett (1998) describes that its inclusion in the Uniform Guidelines was based on guidelines developed by the Technical Advisory Committee on Testing and published by the State of California Fair Employment Practice Commission (FEPC) in 1971. He recounts a discussion regarding the rule in one of the committee member’s living room that 85% seemed too high and 75% seemed too low. Apparently 4/5ths or 80% was just right.

Other Important Considerations Related to the 4/5ths Rule

The 4/5ths rule was never intended to be a hard and fast rule. The Uniform Guidelines actually call it a “rule of thumb.” It was really meant as a trigger to indicate when greater scrutiny was needed. As a practitioner, however, I do not want to be on the wrong side of the 4/5ths rule. It has become enshrined as a critical threshold and once you cross (go lower than) than 80% you open yourself and your organization to all sorts of issues and headaches.

Also, just because the 4/5ths rule has not been violated does not automatically mean that no discrimination has taken place. The rule merely places a numerical basis for drawing an initial inference about discrimination in the form of adverse impact. There may still be unlawful discrimination even if the rule is not violated. Thus, the 4/5ths does not imply that the Guidelines approve up to 20% discrimination.

There are a lot of other technical details about adverse impact and the 4/5ths rule. Here are a few more issues for consideration.

Who is an applicant?
It depends on the specifics of the selection procedure, but in general an applicant is a person who has followed the employer’s procedure to express interest in a particular position and met the basic qualifications. A person who voluntarily withdraws from the process is no longer considered an applicant.

Should the overall (total) selection process evaluated or can subcomponents be evaluated?
First the overall selection process should be evaluated for adverse impact using the 4/5ths rule. If there is no adverse impact then under most, but not all, cases no further analysis is required. However, if the 4/5ths rule is violated then each individual subcomponent of the process should be analyzed.

Should all calculations be made for all groups regardless of their size?
No. If the qualified applicant pool is less than 2% of the relevant labor market then the group does not need to be included in any analyses.

Do you need to compare selection rates for subgroups such as White males, White females, Black males, and Black females or can you just do analysis based on sex and then another on race?
There is obligation to compare subgroups, such as White males and Black males. You are only required to make comparisons like males and females, White and Black.

Can tests of statistical significance be used instead or in addition to the 4/5ths rule?
There is nothing that says tests of significance can’t be used. However, the 4/5ths rule is practical in that it is an easy to use and easy to understand rule of thumb. Statistical tests are more complicated, harder to explain, and can be influenced by a bunch of factors including small and large sample sizes.

Are the Guidelines and the 4/5ths Rule Out of Date?

Time does not stand still in the area of employee selection. Our collective knowledge has grown greatly since 1978 when the Uniform Guidelines were published. Testing and employee selection is a very popular research area with literally thousands and thousands of studies published since 1978. Because of this, some have argued that the Uniform Guidelines are out of date and detriment to the field of employee selection. McDaniel, Kepes, and Banks (2011) published a focal article stating this inviting 11 commentary articles debating the issue.

There were good points all around. The Guidelines are probably out of date scientifically and treat adverse impact and group differences too simplistically. But, then the Guidelines were never mean to be a scientific document.

Regardless, the Guidelines are what has been used for nearly 40 years and have been in embedded in countless court cases. Furthermore, selection is not just a scientific issue. There are complicated social and political issues as well that come into play.

One advantage that the Guidelines have is that they are a known entity and stable. There is no guarantee that a replacement would be an improvement.

Why is it Useful to Understand the 4/5ths Rule?

This was just a simple introduction to the 4/5ths rule. There is a lot more to read and understand. There are a lot of technical writings and there are a lot of court cases.

Sure some of this my make your eyes glaze over and it might be tough to get through the readings, but knowledge of selection tests and legal issues are important. Those who specialize in the topic make very good money. Even if you are not an expert in selection and adverse impact it is a valuable skill to have making you more employable. The American Institutes for Research (2013) performed a study for the Society for Human Resource Management on the state of HR education. They found that knowledge of staffing was the most valuable skill increasing a student’s marketability and employability. This was true at the undergraduate level and even truer at the graduate level.

Where to Find More Information

If you would like to read the actual Guidelines and Questions and Answers you can find them at the websites below.

Test Yourself

1. What landmark court case played a major role in the conceptualization of adverse impact?

Plessy v. Ferguson
Albemarle Paper Co. v. Moody
Griggs v. Duke Power


2. When where the Uniform Guidelines published?



3. If racial group A has a selection ratio of .80 and racial group B has a selection ratio of .65 has the 4/5ths rule been violated?



4. One hundred people applied for a job. Of these, 78 were White and 22 were Asian. After a series of written tests, 53 White applicants and 13 Asian applicants were hired. Has the 4/5ths rule been violated.



5. There are 153 applicants who interviewed for a job. Of the 30 Asian applicants, 15 were hired, and of the 123 White applicants, 45 where hired. Has the 4/5ths rule been violated?




American Institutes for Research (2013). Society for Human Resource Management’s state of human resource education study. Alexandria, VA.

Barrett, R. S. (1998). Challenging the myths of fair employment practices. Westport, CT: Quorum Books/Greenwood Publishing Group.

Equal Employment Opportunity Commission (EEOC), Civil Service Commission, Department of Labor, & Department of Justice. (1978). Uniform guidelines on employee selection procedures. Federal Register, 43, 38290–39315.

Equal Employment Opportunity Commission, & Civil Service Commission. Department of Labor, Department of Justice (1979). Adoption of questions and answers to clarify and provide a common interpretation of the Uniform Guidelines on employee selection procedures. Federal Register, 44, 11996-12009.

Griggs v. Duke Power Company (1971), 401 U.S, 424.

Mcdaniel, M. A., Kepes, S., & Banks, G. C. (2011). The Uniform Guidelines are a detriment to the field of personnel selection. Industrial and Organizational Psychology, 4(4), 494-514.