Academia:
* Early stages (PhD application and admissions): GPA from undergraduate and (sometimes) master's programs are heavily scrutinized during PhD application. Strong grades demonstrate academic aptitude and are vital for getting accepted into a top program. During the PhD itself, good grades (particularly in core coursework) can influence funding opportunities, teaching assignments, and mentorship relationships. A significantly poor performance can raise concerns about a candidate's ability to complete the degree.
* Post-PhD (Job Market): While a perfect GPA isn't expected nor necessarily a deal-breaker, consistently strong performance throughout the doctoral program suggests diligence and research capabilities. However, the quality and impact of the dissertation far outweighs minor variations in coursework grades. Publications, conference presentations, teaching experience, and strong letters of recommendation become much more important in securing a postdoc or faculty position.
* Advancement: Once in academia, research productivity (publications, grants, citations), teaching effectiveness, and service to the university are the primary drivers of promotion and tenure. Past grades are rarely, if ever, discussed in this context.
Industry:
* Relevance: In industry, PhD grades are usually not a significant factor in hiring decisions. The focus is overwhelmingly on skills, experience (internships, projects), and the relevance of the research to the company's needs.
* Specific roles: For highly specialized roles requiring deep subject matter expertise (e.g., research scientist in pharma or tech), a strong PhD record might be slightly more important. But even then, it's usually secondary to demonstrable abilities, practical skills, and the applicant's ability to solve industry-relevant problems.
* Advancement: In industry, promotions are primarily based on performance reviews, project success, leadership skills, and contributions to the company's bottom line. Academic grades from years ago hold almost no weight.
In Summary:
While good PhD grades are advantageous initially (especially for PhD admission), their impact diminishes significantly after graduation. Strong research output, publications, networking, practical skills, and impactful contributions to the field (academia or industry) are far more influential in determining career success. A consistently mediocre record can be overshadowed by exceptional research, while a brilliant GPA doesn't guarantee a successful career without the right skills and achievements.