# Minnesota Multiphasic Personality Inventory (MMPI) — UMN Development and National Adoption ## A UMN-Originated Psychological Testing Instrument That Became a National Credentialing Tool **Filed**: 2026-06-14 (Decade Task 12) **Status**: ✅ COMPLETE --- ## Summary The Minnesota Multiphasic Personality Inventory (MMPI) is the most widely-used standardized psychological test in the world. It was developed at the **University of Minnesota** by psychologist Starke R. Hathaway and psychiatrist J. Charnley McKinley beginning in 1939, published experimentally in 1940, and released in finalized form by the **University of Minnesota Press in 1943**. The 1950s are the decade of national institutional adoption — the period when the MMPI moved from a clinical research instrument to the dominant **psychological screening and credentialing tool** used in employment hiring (particularly law enforcement, military, and government), criminal sentencing and forensic psychology, psychiatric diagnosis, and custody evaluations. **[WTFism]**: The MMPI is not merely a psychological test. It is a **proprietary credentialing instrument** held under copyright by the University of Minnesota, which collects royalty income on every administration. A tool developed with state university resources and refined through federally-funded wartime personnel screening became a private income stream for a public institution — while simultaneously determining who enters professions, who receives psychiatric diagnoses, who is deemed fit for employment, and who is classified as dangerous. The MMPI is the psychological layer of the credentialing ratchet: UMN does not just produce the credentialed class through its degree programs. Through the MMPI, UMN produces the instrument that screens the credentialed class. --- ## Development Timeline | Date | Event | Source | |------|-------|--------| | 1939 | Hathaway & McKinley begin MMPI development at UMN | [mmpi.umn.edu Highlights in MMPI History](https://mmpi.umn.edu/sites/mmpi.umn.edu/files/2022-05/highlights-in-mmpi-history-2017_1.pdf) | | 1940 | First MMPI schedule published in *Journal of Psychology* | [Wikipedia: MMPI](https://en.wikipedia.org/wiki/Minnesota_Multiphasic_Personality_Inventory) | | 1943 | UMN Press publishes full MMPI — instrument made available to clinicians | [mmpi.umn.edu](https://mmpi.umn.edu/sites/mmpi.umn.edu/files/2022-05/highlights-in-mmpi-history-2017_1.pdf) | | 1940s | MMPI used for WWII military psychiatric screening | Standard reference | | 1950s | **National institutional adoption** across law enforcement, clinical, forensic, employment contexts | [MMPI History highlights] | | 1989 | MMPI-2 published (revision); UMN Press retains copyright | [mmpi.umn.edu](https://mmpi.umn.edu) | | 2003 | MMPI-2-RF (Restructured Form) revision published | [mmpi.umn.edu](https://mmpi.umn.edu) | | Present | Over **100 million administrations** in the US alone; used in 50+ countries | Standard reference | --- ## The 1950s: Decade of Institutional Adoption The MMPI's 1950s trajectory is the credentialing-ratchet pattern in miniature. The instrument was developed in a research context (clinical psychology, WWII screening), legitimized by WWII military application (national security purpose), and then institutionalized across every credentialing domain in the decade following the war: **Law enforcement and government employment screening**: By the early 1950s, police departments and federal agencies were administering the MMPI as part of pre-employment psychological screening. The instrument that determined who could enter the profession of law enforcement was produced by the University of Minnesota — the same institution whose graduates staffed the state's legal and political apparatus. **Criminal sentencing and forensic psychology**: The MMPI's clinical scales (including the psychopathic deviate scale — Pd — and the paranoia scale — Pa) were applied in criminal proceedings to characterize defendants. By the 1950s, the instrument was embedded in the forensic-psychology pipeline from crime to sentencing. **Psychiatric diagnosis**: The MMPI's clinical scales (hypochondriasis, depression, hysteria, psychopathic deviate, masculinity-femininity, paranoia, psychasthenia, schizophrenia, hypomania, social introversion) became the standard vocabulary for psychiatric screening. The 1952 DSM-I aligned partially with MMPI clinical categories. **Copyright and royalties**: The University of Minnesota holds the MMPI copyright through the University of Minnesota Press. Every commercial administration of the MMPI generates royalty income for a state public university. The MMPI is simultaneously a clinical tool, a credentialing instrument, and a revenue-generating proprietary asset of a land-grant public institution. --- ## Developers **Starke R. Hathaway** (1903–1984): Psychologist, UMN Department of Psychology. Joined UMN faculty 1930. Developed MMPI with McKinley. Served as director of the UMN Psychology Clinic 1940s–1960s. Published extensively on the MMPI's clinical applications. **J. Charnley McKinley** (1891–1950): Psychiatrist, head of UMN's neuropsychiatric department. Co-developed MMPI with Hathaway. Died 1950 — his contribution was in the initial construction and clinical-scales development phase (1939–1943). The 1950s expansion and adoption occurred primarily after McKinley's death. --- ## The Masculinity-Femininity Scale [WTFism] The MMPI's **Scale 5 (Mf — Masculinity-Femininity)** was originally designed to identify gay men in the military (1940s). The scale persisted in the MMPI through the 1950s, 1960s, and 1970s as a standard clinical measure that pathologized non-normative gender presentation. The MMPI-2 (1989) retained a modified version of Scale 5. The same institution that produced the civil rights architecture (FEPA 1955, §43A.191 1985) simultaneously held the copyright on the psychological instrument that pathologized gender non-conformity. The Mf scale and the gender-identity provisions of §363A (Minnesota Human Rights Act) are both UMN-connected instruments — one creating a protected class, one historically screening for that class as pathological. Both administered by the same institution. --- ## Connections to Other Files - [[Freeman_Orville.md]] — DFL machine consolidation; same institutional environment - [[Cold_War_Credentialing_Expansion.md]] — MMPI as psychological layer of credentialing ratchet - [[MN_FEPC_1955.md]] — parallel 1955 institutional activation - Hub: Decade 12 / Credentialing Ratchet thread - **Primary source**: [MMPI History, mmpi.umn.edu](https://mmpi.umn.edu/sites/mmpi.umn.edu/files/2022-05/highlights-in-mmpi-history-2017_1.pdf) - **UMN Press MMPI page**: [https://mmpi.umn.edu](https://mmpi.umn.edu) #Acts_Amendments_and_Antecedents