## Facts

- Arlene Horner, a female physical education teacher, was hired by Mary Institute for the 1974–75 school year to teach mainly in the middle and upper schools (grades 5–12), using an existing curriculum.
- Mary Institute, a nonprofit operating three private schools in St. Louis, hired Ralph Thorne, a male physical education teacher, in the same year; Horner and Thorne had roughly comparable experience and qualifications.
- Horner accepted a starting salary of $7,500.
- Thorne rejected an initial offer comparable to Horner’s and accepted a renewed offer of $9,000.
- Over the next three years, Thorne received annual salary increases that exceeded Horner’s by $200 to $800 each year.
- Evidence showed Thorne assumed additional responsibilities, including developing a new lower-school curriculum and taking on extra initiatives; the administration rated his performance highly.
- The district court found Horner taught an established curriculum and was not viewed as particularly innovative during the relevant period.
- Horner introduced pension-plan statistics suggesting higher average pay for male employees, but the data mixed teaching and non-teaching staff and included lower-paid female clerical workers.

## Issues

1. Whether Horner established a prima facie Equal Pay Act claim by proving she was paid less than a male employee for substantially equal work requiring equal skill, effort, and responsibility under similar working conditions.
2. Whether, assuming a prima facie case, Mary Institute proved the pay differential was based on factors other than sex, including negotiation, additional responsibilities, and superior performance.

## Decision

- The Eighth Circuit affirmed the district court’s judgment for Mary Institute after a bench trial.
- The court held the district court did not clearly err in finding Horner failed to prove her job was substantially equal to Thorne’s in skill, effort, and responsibility.
- The court further held that, even if substantial equality were assumed, the record supported a finding that the wage differential was explained by factors other than sex, including Thorne’s negotiated starting salary, extra duties, and stronger performance.
- The court agreed that Horner’s aggregate statistical evidence did not establish a sex-based pay practice or undermine the case-specific findings.

## Legal Principles

- To prove a prima facie Equal Pay Act violation, a plaintiff must show different wages paid to opposite-sex employees for substantially equal work requiring equal skill, effort, and responsibility, performed under similar working conditions.
- Whether two jobs are “substantially equal” is primarily a factual question; appellate review of the trial court’s findings is for clear error.
- If a prima facie case is shown, the employer avoids liability by proving the wage differential is justified by a statutory exception, including “any other factor other than sex.”
- Negotiated starting pay, additional job responsibilities (including qualitatively different duties), and documented superior performance can qualify as “factors other than sex.”
- Undifferentiated statistical comparisons that mix job categories and fail to control for job content may be insufficient to prove an Equal Pay Act violation.

## Conclusion

The Eighth Circuit held that the evidence supported findings that Horner’s position was not substantially equal to her male comparator’s and that any pay difference was attributable to non-sex-based factors, so Mary Institute was not liable under the Equal Pay Act.


Horner v. Mary Inst., 613 F.2d 706 (8th Cir. 1980)