Comparing major declaration, attrition, migration, and completion in physics with other STEM disciplines

Based on a decade of institutional data, this study reveals that physics suffers from the lowest enrollment, highest attrition, and lowest female participation among STEM disciplines, attributing these inequitable outcomes to cultural stereotypes, uninspiring introductory courses, and a lack of intentional retention efforts.

The Gist

Imagine a massive university as a giant, bustling train station. Thousands of students arrive every year, looking for a train to take them to their future careers. Some trains are packed (like Engineering or Biology), while others are nearly empty.

This research paper is like a detective story where the authors (Kyle, Danny, and Chandralekha) looked at the station's logs from the last 10 years to see who got on which train, who jumped off, and who actually made it to the final destination. They focused specifically on the Physics train and compared it to all the other Science, Technology, Engineering, and Math (STEM) trains.

Here is what they found, explained simply:

1. The Physics Train is the Smallest and Most Leaky

Out of all the STEM trains, the Physics train has the fewest people on it. But the real problem isn't just that it's small; it's that people keep jumping off.

• The Analogy: Imagine a bucket with a hole in the bottom. You pour water in (students declaring the major), but the water leaks out faster than any other bucket.
• The Data: Physics had the highest rate of students dropping the major. More than one-third of the students who said, "I'm going to be a physicist," changed their minds and left before graduating.

2. The "One-Way Street" Problem

Most other majors are like a busy roundabout. Students might switch from Biology to Chemistry, or from Math to Engineering, and sometimes they even switch back.

• The Physics Reality: The Physics train is a one-way street. Students hop off, but almost no one hops on from other trains. Once you leave the Physics train, you rarely come back. It's a "leaky pipeline" where the flow is only outward.

3. The "Brilliance" Stereotype (The Ghost in the Station)

Why are so few women on the Physics train? The authors suggest it's because of a scary ghost haunting the station: The Stereotype of "Brilliance."

• The Metaphor: There is a common belief in society that Physics is only for "geniuses" or "natural-born geniuses," and that these geniuses are usually men. It's like a sign on the door that says, "Only the smartest, most naturally gifted men need apply."
• The Result: Women (and many men) hear this ghost story and think, "I'm not a genius, so I don't belong here." They don't even get on the train, or they jump off the moment the ride gets bumpy. The paper notes that Physics and Computer Science have the lowest number of women, exactly matching fields where this "brilliance" myth is strongest.

4. The "First-Year Bump"

The authors found that the first-year physics class is often where the magic (or the magic killer) happens.

• The Analogy: Imagine the first year of physics is like a hazing ritual. Instead of being a welcoming guide, it can feel like a test to see if you are "worthy." If the environment feels cold, unwelcoming, or like it's only for the "chosen few," students—especially women—decide, "This isn't for me," and they leave.
• The Missed Opportunity: The paper argues that physics is actually a great subject that teaches you how to think and solve problems (skills useful for any job). But because the culture is often cold and unhelpful, students miss out on these skills.

5. The "Graduate School" Blind Spot

The authors point out a weird attitude in many big university physics departments.

• The Metaphor: The professors often act like they are only training the next generation of "Super-Scientists" (people who will get PhDs and teach). They often ignore the regular students who just want to learn physics to become engineers, doctors, or data analysts.
• The Result: If a student says, "I love physics but I want to be an engineer," the department might shrug and say, "Well, if you aren't going to be a professor, you don't need our help." This makes students feel unvalued and pushes them to switch to a different major where they feel supported.

The Bottom Line

The paper concludes that the low number of physics majors and the high number of dropouts aren't because the students aren't smart enough. It's because the culture of the "Physics Train" is broken.

To fix it, the university needs to:

1. Stop the "Genius" Myth: Show students that you don't need to be a born genius to do physics; you just need to work hard and get support.
2. Fix the Welcome Mat: Make the first-year classes friendly and supportive so students don't jump off immediately.
3. Value Everyone: Professors need to care about all physics students, not just the ones who want to become professors.

If they do this, the "leaky bucket" might finally get patched, and more diverse students might find their way onto the Physics train and stay there until they reach the finish line.

Technical Summary

1. Problem Statement

Despite increasing efforts to improve equity and inclusion in Science, Technology, Engineering, and Mathematics (STEM) fields, significant disparities persist, particularly in physics. The authors identify a critical gap in understanding the systemic nature of these inequities through the lens of institutional data. While prior research has focused on historical societal norms or qualitative experiences, there is a lack of quantitative analysis regarding the specific trajectories of students—specifically declaration, attrition (dropping), migration (transferring between majors), and degree completion—comparing physics to other STEM disciplines.

The study addresses the hypothesis that physics culture at large research universities is often characterized by an "exclusionary" mentality (e.g., the belief that physics requires innate "brilliance" and is only for men), leading to:

• Low enrollment numbers compared to other STEM fields.
• High attrition rates among declared majors.
• A lack of intentional recruitment and retention strategies, particularly for women and underrepresented groups.
• A uni-directional flow of students out of physics, with few migrating into it from other fields.

2. Methodology

Data Source and Sample:

• Institution: A large, public, high-research doctoral university in the USA.
• Dataset: 10 years of de-identified institutional records (Fall 2009–Spring 2019).
• Sample Size: $N = 18,319$ undergraduate students from the School of Engineering and the School of Arts and Sciences.
• Demographics: 49.9% female; 77.7% White, 11.1% Asian, 6.8% Black, 2.5% Hispanic, 2.0% other/multiracial.
• Selection Criteria: Students who enrolled in a Fall semester, provided self-reported gender, and either graduated or were inactive for at least one year by Spring 2019.

Variables and Measures:

• Gender: Categorized as "Male" (M) or "Female" (F) based on self-reporting.
• Majors: Categorized into STEM clusters (Biological Sciences, Computer Science/Engineering, Mathematics/Physical Sciences) and specific non-STEM majors (Economics, Psychology, Other).
• Key Metrics Calculated:
  1. Major Declaration: Total unique students declaring a major.
  2. Attrition Rate: Percentage of students who declared a major but subsequently dropped it.
  3. Migration: The destination major for students who dropped a specific major (including "No Degree").
  4. Degree-Earning Rate: Percentage of declared majors who ultimately earned a degree in that specific major.
• Analysis Tools: Statistical analysis performed in R using the tidyverse package. Proportions were calculated with standard errors.

Theoretical Framework:
The study utilizes an Equity Framework consisting of three pillars:

1. Equitable opportunity and encouragement to learn.
2. Equitable and inclusive learning environments (support, mentoring, sense of belonging).
3. Equitable learning outcomes (comparable retention and motivational beliefs across demographics).

3. Key Contributions

• Longitudinal Institutional Analysis: Provides a rare, large-scale, 10-year quantitative analysis of student flow (declaration $\to$ attrition $\to$ migration $\to$ completion) across multiple STEM disciplines.
• Identification of Physics as an Outlier: Establishes physics as having the lowest enrollment and the highest attrition rates among all STEM disciplines studied.
• Uni-directional Migration Pattern: Demonstrates that while students migrate in and out of most STEM fields, physics exhibits a predominantly uni-directional outflow (students leave physics, but rarely transfer into physics from other majors).
• Cultural Diagnosis: Links quantitative attrition and gender disparity data directly to cultural factors, specifically the "brilliance" stereotype and the lack of undergraduate support in large research physics departments.

4. Key Results

A. Major Declaration Patterns:

• Enrollment Volume: Physics has the lowest number of unique students declaring the major compared to all other STEM disciplines.
• Gender Imbalance: Physics and Computer Science have the lowest representation of women.
  • In Physics and Astronomy, approximately 80% of majors are men.
  • In contrast, Biological Sciences show a near-even split.
• Declaration Timing: Most students declare majors in their second year (terms 3–4). Engineering students declare in term 1; Computer Science students declare later (terms 5–6) due to prerequisite hurdles.

B. Attrition Rates:

• Highest Attrition: Physics has the highest attrition rate of all STEM majors (>33% of declared students drop the major).
• Comparison: Physics, Mathematics, and Chemistry have the highest drop rates. Computer Science, Non-STEM, and Psychology have the lowest.
• Gender Differences: While overall attrition patterns are similar for men and women, the absolute numbers are skewed by the low initial number of women in physics.

C. Migration and Degree Trajectories:

• Uni-directional Flow: Students dropping Physics frequently migrate to Mathematics or Engineering. However, very few students dropping other majors (e.g., Math, Engineering) choose to transfer into Physics.
• Degree Completion:
  • Physics has the lowest degree-earning rate (~65%) among STEM majors.
  • Computer Science and Psychology have the highest completion rates (~88–94%).
  • Note: The high completion rate in Computer Science is partially attributed to the late declaration policy, which filters out students before they officially declare.
• Post-Drop Outcomes: Students who drop Physics are more likely to earn a degree in Mathematics or Engineering. Those who drop Computer Science, Non-STEM, or Psychology have a >50% chance of earning "No Degree."

D. Gender-Specific Findings:

• Women in Physics: Women comprise only ~20% of physics majors.
• Attrition Nuance: While statistical attrition rates between men and women in physics are comparable (due to low sample size and large error bars), qualitative interviews suggest women may be more likely to abandon the intent to major in physics after introductory courses, even before official declaration.
• Completion: Among those who declare, 75% of women and 63% of men eventually earn a physics degree, though this difference is not statistically significant due to sample size constraints.

5. Significance and Implications

Theoretical Significance:
The study validates the "brilliance" stereotype hypothesis (Leslie et al., 2015), showing that disciplines perceived as requiring innate genius (like physics) suffer from both low female enrollment and high attrition. It frames these statistics not merely as academic failures but as signatures of an inequitable culture.

Practical Implications:

• Cultural Shift Required: Large research universities must move away from a "sink-or-swim" mentality where faculty assume undergraduates not pursuing graduate school are "unproductive."
• Intentional Recruitment: Departments must actively recruit and retain students who may not intend to become professional physicists but value the critical thinking skills physics offers.
• Introductory Course Reform: Since students declare majors in their second year, the first-year introductory physics courses are critical. These courses must be redesigned to be inclusive, student-centered, and supportive to prevent early attrition, particularly among women.
• Faculty Incentives: Institutions must provide incentives for faculty to engage in mentoring and retention efforts for undergraduates, regardless of their career trajectory.

Future Directions:
The authors call for similar studies at different institution types (e.g., primarily undergraduate institutions) and across different countries to determine the generalizability of these findings. They also suggest future research into intersectionality (e.g., the experiences of women of color) to address compounded inequities.