For years, standard economic arguments have suggested that the gender pay gap is mostly a matter of career selection—that men simply gravitate toward higher-paying industries like engineering, while women are concentrated in lower-paying fields like education or caregiving.
However, a massive international study led by researchers at the University of California, Irvine, reveals that this explanation only covers half the truth. The other half is far more direct: **women are frequently paid less than the men sitting right next to them, performing the exact same job for the exact same employer.**
The study, which analyzed comprehensive employment and earnings data across 15 industrialized nations, found that this "within-job" pay discrimination is a systemic, global issue.
Key Findings Across the Globe
The research team tracked full-time workers between the ages of 30 and 55, discovering wide variations in how countries handle wage equity:
* **The Total Earnings Gap:** The overall difference in take-home pay between men and women ranged from a low of 10% in Hungary to a high of 41% in South Korea. The United States landed near the bottom of the pack, holding the fourth-highest overall wage gap at 30%.
* **The "Same Job" Disparity:** When looking strictly at men and women with the exact same job title at the same company, the gap persisted. Japan had the worst within-job discrepancy at 26%. The U.S. ranked as the third-worst, with women earning 14% less than their direct male peers. France and Denmark performed the best, though women there still faced a 7% wage penalty for the same roles.
* **The 50/50 Split:** Ultimately, the researchers concluded that within-job pay differences account for roughly half of the total gender wage gap globally.
Why This Changes the Conversation
"Previous research and policies have put the onus for gender pay inequity purely on occupational choices," explained Andrew Penner, a professor of sociology at UCI and the study's lead author. "We found this to be only half of the story. The other half is comprised of women who are paid less than the men they're working next to... And this isn't just a one-country problem; it's everywhere."
Because the root causes of the pay gap are split, policymakers and human resources departments cannot rely on a single solution.
| If the cause is... | The solution requires... |
| --- | --- |
| **Occupational Sorting** (Men and women routed into different fields) | Removing hiring and promotion barriers that block women from entering high-paying leadership or technical roles. |
| **Within-Job Disparity** (Different pay for the exact same work) | Enacting stricter corporate pay transparency, conducting regular salary audits, and enforcing equal pay laws.
While the study offers a sobering look at workplace inequality, it also notes a silver lining: both the overall wage gap and the "same job" pay discrepancies have steadily decreased over the last few decades in 12 of the 15 countries analyzed.
The next phase of the research aims to look closely at individual corporate structures to understand why some companies manage to achieve perfect pay parity while others lag severely behind.