Estimating Carbon Emission and Cost Savings from Virtual Dermatology Residency Interviews

COVID-19 has transformed dermatology residency recruitment into a largely virtual process. Benefits include increased environmental and cost sustainability, whereas drawbacks include fewer in-person opportunities to determine program fit. In light of stakeholders soon deciding how best to move forward, we provide an estimate of carbon emission and applicant cost savings associated with maintaining virtual residency recruitment.

To inform our predictions, we extracted applicant medical school and residency information from a previously published cohort of 2,580 allopathic medical students matching into dermatology, spanning 15 years, and corresponding to the release of National Resident Matching Program (NRMP) annual reports.¹

To generate carbon emission estimates, we used the GeoPy Python library, OpenCage Geocoding Application Programming Interface (API), and Google Distance Matrix API to calculate roundtrip distance in miles between applicant medical school city and residency program city to estimate interview distance (ID). This distance was multiplied by Environmental Protection Agency carbon emission per mile estimates to obtain carbon emissions per interview in kilograms of CO₂ (CE_Interview).² Travel method was assumed to be car if roundtrip distance was ≤400 miles or airplane if >400 miles. CE_Interview was multiplied by average number of interviews per applicant and total number of dermatology applicants, per NRMP, to obtain carbon emissions for all dermatology applicants.³

To generate inflation-adjusted cost savings estimates, we considered in-person interview costs previously estimated at $500 per interview.⁴ In-person interview costs were multiplied by total number of applicants and median number of interviews, again per NRMP, to obtain total cost savings per year.³

Among 2,580 matched dermatology applicants, median ID and CE_Interview were 496 miles and 101 kilograms CO₂, respectively (Table 1). Applicants save an estimated $4,696 with virtual recruitment (Table 2).

Table 1:

Estimated Carbon Emissions Associated with In-Person Residency Interviews Across Academic Years Corresponding to Historic National Resident Matching Program Reports

		2007	2009	2011	2014	2016	2018	2021a
Median Interview Distance (Round-trip, Miles)		436	500	471	608	587	471	424
Median CEInterview (kg of CO2)b		92	105	98	106	108	106	94
Interviews	Matched	8.0	8.5	9.0	8.9	8.9	9.3	9.9
	Unmatched	3.0	3.8	3.1	3.8	4.2	4.3	4.5
Applicants	Matched	249	286	307	352	339	340	388
	Unmatched	158	125	80	111	93	72	70
Total Carbon Emissions (Thousands of kg CO2) c		350	423	493	666	557	576	645

Abbreviations: CE, carbon emission; kg, kilogram

^a2021 interview distance and carbon emissions are theoretical as in-person interviews were not conducted during this cycle due to COVID-19.

^b2021 Environmental Protection Agency for CO₂ emissions were utilized for calculations: 0.341 kg/vehicle mile for passenger cars; 0.131 kg/passenger mile for flights 400–2300 miles; and 0.161 kg/passenger-mile for flights greater than 2300 miles.

^cCalculated by multiplying median CEInterview * [(# of matched applicants * average number of interviews per matched applicant) + [(# of unmatched applicants * average number of interviews per unmatched applicant)]. Number of applicants and number of interviews obtained from National Resident Matching Program.

Table 2:

Inflation-Adjusted Estimated Costs Savings with Virtual Residency Interviews Across Academic Years Corresponding to Historic National Resident Matching Program Reports

		2007	2009	2011	2014	2016	2018	2021
Applicants	Matched	249	286	307	352	339	340	388
	Unmatched	158	125	80	111	93	72	70
Interviews	Matched	8.0	8.5	9.0	8.9	8.9	9.3	9.9
	Unmatched	3.0	3.8	3.1	3.8	4.2	4.3	4.5
Savings Per Applicant a	Matched	$4,859	$5,160	$5,464	$5,404	$5,405	$5,463	$6,008
	Unmatched	$1,822	$2,307	$1,882	$2,307	$2,551	$2,609	$2,731
Total Savings All Derm Applicants (Millions of Dollars)b		$1.5	$1.8	$1.8	$2.2	$2.1	$2.1	$2.5

^aBased on previous estimate of $500 (in 2014 dollars) per in-person interview * Avg. # of accepted interviews per applicant for each corresponding year.

^bCalculated by multiplying Cost Per Applicant * Total number of dermatology applicants for each corresponding year.

Extrapolated across all dermatology applicants, virtual recruitment saves ~530 thousand kilograms CO₂ annually, the average annual energy use of 67 households. As the consequences of anthropogenic climate change continue to manifest, the medical community must act to mitigate these effects. Cost savings extrapolate to ~$2 million annually across all dermatology applicants, which would benefit medical graduates saddled with an ever-increasing debt burden.

Limitations include sparse data on unmatched applicants and relying on distance between medical school and residency program city as a surrogate for average distance traveled per interview, as we cannot access individual applicant interview data. As our methodology assigns CE=0 for applicants matching at home programs, CE_Interview is likely an underestimate. Furthermore, our $500 estimate per interview is extrapolated from a survey study from urology, whose costs may differ from dermatology, and our 400-mile threshold distinguishing car and plane travel for interviews was an educated estimate.⁴

Our study considered interview costs and carbon emissions as proxies for financial and environmental savings. However, other variables including program cost savings and non-carbon emissions (e.g., nitrogen oxides, aerosols) were not studied. Future research should assess how advantages of in-person interviewing (e.g., better assessing program/city fit) weigh against the disadvantages of added cost and carbon emissions. Stakeholders should consider these benefits while minimizing drawbacks when determining how to proceed with the residency recruitment process.