National Academies Press: OpenBook
« Previous: 2 Sources of the Data
Suggested Citation:"3 PAIRWISE CORRELATIONS." National Research Council. 2011. Research-Doctorate Programs in the Biomedical Sciences: Selected Findings from the NRC Assessment. Washington, DC: The National Academies Press. doi: 10.17226/13213.
×

3

PAIRWISE CORRELATIONS

In its statement of task, the panel was asked to examine the correlations among a number of the variables in the Assessment (see Box 1-1). Several of the correlations are presented in this chapter, including correlations of student time to degree and completion rates with various characteristics of doctoral programs, and correlations between the diversity of a program’s faculty and the diversity of its students. All of the data are drawn from the tables of pairwise correlations found in Appendix D, in which any correlations greater than or equal to 0.31 are highlighted.

The correlations provide insights into the relationships between characteristics that can be explored further. The panel focused its attention on correlation coefficients greater than or equal to 0.3 because they are nontrivial and they may display, in the panel’s view, important relationships between program characteristics. Pairwise correlations uncover these potential relations of interest. Where associations are detected that, based upon prior knowledge, are judged indicative of relationships worth further study, adjustments for potential confounding variables must be made. Such adjustments are beyond the scope of this brief report.

Table 3-1 provides the correlations of student median time to degree and average cohort completion rate with three measures of faculty research productivity: average publications per faculty member, average citations per faculty member, and the percent of faculty with grants (see Appendix C for definitions). There is little relation between the average cohort completion rate and the productivity measures, with the exception of faculty with grants in physiology. The correlation of median time to degree and grants is also strong for physiology, and the correlations of median time to degree with citations per publication are strong for physiology, biomedical engineering and bioengineering, genetics and genomics, and immunology and infectious disease. Correlations in these four fields do not meet the 0.3 level with respect to publications per faculty, although they range from 0.179 to 0.272. The only field with a strong correlation between median time to degree and publications per faculty is nutrition. Where appreciable correlations exist between median time to degree and measures of faculty research productivity, greater research productivity is associated with longer times to degree.

______________

1 Correlations of 0.295 and higher were rounded to 0.3.

Suggested Citation:"3 PAIRWISE CORRELATIONS." National Research Council. 2011. Research-Doctorate Programs in the Biomedical Sciences: Selected Findings from the NRC Assessment. Washington, DC: The National Academies Press. doi: 10.17226/13213.
×

Table 3-1 Correlations of Median Time to Degree and Average Cohort Completion with Publications, Citations, and Grants

Fields Correlation with Median Degree Time to Correlation witd Average Cohort Completion
Average Pubs per Faculty Average Cits/Pubs Percent Faculty witd Grants Average Pubs per Fac Average Cits/Pubs Percent Faculty witd Grants
Biochemistry, Biophysics, and Structural            
Biology 0.052 0.166 0.077 0.123 0.089 0.094
Biomedical Engineering and Bioengineering 0.185 0.369 0.018 -0.184 0.015 0.148
Cell and Developmental Biology 0.014 0.128 0.081 0.087 0.057 -0.041
Genetics and Genomics 0.181 0.364 0.23 0.229 -0.02 0.149
Immunology and Infectious Disease 0.179 0.327 0.189 -0.067 -0.05 -0.02
Integrated Biological and Biomedical Sciences -0.12 0.058 0.04 0.056 0.021 0.014
Microbiology 0.232 0.289 0.302 -0.072 -0.087 -0.201
Neuroscience and Neurobiology 0.059 0.21 0.169 0.036 0.046 -0.03
Nutrition 0.475 0.216 0.202 -0.037 0.085 -0.095
Pharmacology, Toxicology, and Environmental            
Health -0.01 0.29 0.058 0.136 -0.095 0.117

Suggested Citation:"3 PAIRWISE CORRELATIONS." National Research Council. 2011. Research-Doctorate Programs in the Biomedical Sciences: Selected Findings from the NRC Assessment. Washington, DC: The National Academies Press. doi: 10.17226/13213.
×

Table 3-2 correlates median time to degree and average completion rate with GRE General Test scores and the average number of Ph.D.’s in each program. The correlations between cohort completion and both average GRE and average PhDs are uniformly low, and in several fields are negative. The exception is physiology. There is a positive correlation with respect to median time to degree and both average GRE scores and average Ph.D.’s produced, but only in nutrition are both strongly correlated. In biomedical engineering and bioengineering there is a strong correlation between median time to degree and average number of Ph.D.’s, and in microbiology a strong correlation between median time to degree and average GRE scores.

TABLE 3-2 Correlations of Median Time to Degree and Average Cohort Completion with GRE Scores

  Correlation with Median Time to Degree Correlation with Average Cohort Completion
Fields GRE Average Average Ph.D.’s 2002 to 2006 GRE Average Average Ph.D.’s 2002 to 2006
Biochemistry, Biophysics, and Structural        
Biology 0.114 0.140 0.094 0.046
Biomedical Engineering and Bioengineering 0.251 0.491 0.080 -0.011
Cell and Developmental Biology 0.093 0.074 -0.022 -0.022
Genetics and Genomics 0.179 0.074 -0.108 0.235
Immunology and Infectious Disease 0.033 0.050 -0.216 0.051
Integrated Biological and Biomedical Sciences 0.111 0.145 -0.181 -0.033
Microbiology 0.319 0.270 -0.075 -0.089
Neuroscience and Neurobiology 0.156 0.150 0.007 0.076
Nutrition 0.487 0.309 -0.055 -0.106
Pharmacology, Toxicology, and Environmental        
Health 0.179 0.038 -0.058 0.103
Physiology 0.223 0.192 0.261 0.295

The correlations in Table 3-3 demonstrate a strong relationship between underrepresented minority faculty and underrepresented minority students in six of the eleven fields:

Biochemistry, Biophysics, and Structural Biology;

Immunology and Infectious Disease;

Microbiology;

Nutrition;

Pharmacology, Toxicology, and Environmental Health; and

Physiology.

For a fuller discussion of underrepresentation see Chapter 5.

Suggested Citation:"3 PAIRWISE CORRELATIONS." National Research Council. 2011. Research-Doctorate Programs in the Biomedical Sciences: Selected Findings from the NRC Assessment. Washington, DC: The National Academies Press. doi: 10.17226/13213.
×

The same relationship does not hold true for gender. The panel found no meaningful correlation between the percent of female faculty in a program and the percent of female students; the correlations are below 0.3 in every biomedical science field. The highest correlation (0.288) is in nutrition. While the average percentage of female students in all fields except biomedical engineering and bioengineering is over or near 50 percent, this is not the case with the average percentage of female faculty (see Appendix E). Only in nutrition is the average percentage of female faculty over 50 percent; the average percentage of female students is over 75 percent. Participation of women in faculty positions in the biomedical sciences is not a new issue. Women have consistently been represented on the faculty of biomedical fields at a rate lower than their proportion in the Ph.D. population.2 Thus, although programs with a higher percentage of minority faculty do indeed seem to attract minority students at a higher rate, the same is not true for women.

TABLE 3-3 Correlations of Percent Female Students with Percent Female Faculty and Percent of Non-Asian Minority Students with Percent Minority Faculty

  Correlation with
Percent Female
Students
Correlation with
Percent Non-Asian
Minority Students
 
  Percent Female Percent Minority
Fields Faculty Faculty
Biochemistry, Biophysics, and Structural Biology 0.170 0.489
Biomedical Engineering and Bioengineering 0.118 0.076
Cell and Developmental Biology 0.004 0.247
Genetics and Genomics 0.109 0.290
Immunology and Infectious Disease 0.014 0.150
Integrated Biological and Biomedical Sciences 0.227 0.529
Microbiology 0.233 0.765
Neuroscience and Neurobiology 0.204 -0.002
Nutrition 0.288 0.531
Pharmacology, Toxicology, and Environmental
Health 0.187 0.370
Physiology 0.086 0.570

The correlations in Appendix D permit examination of many other relationships among the characteristics of doctoral programs, faculty, and students. For example, the relationship between program size (as measured by average number of Ph.D.’s) and research productivity (as measured by faculty publications, citations, and grant awards) may be of particular interest to some university administrators and researchers. Although correlation does not imply causation,

______________

2 Research Training in the Biomedical, Behavioral, and Clinical Research Sciences, National Academies Press, 2011,p. 39.

Suggested Citation:"3 PAIRWISE CORRELATIONS." National Research Council. 2011. Research-Doctorate Programs in the Biomedical Sciences: Selected Findings from the NRC Assessment. Washington, DC: The National Academies Press. doi: 10.17226/13213.
×

it would make sense that, in fields where laboratories are critical to research productivity, programs with larger laboratories would be more productive—even when measured on a per capita basis. This is seen in the relationship between the three measures of research productivity and number of Ph.D.’s, where several fields with higher values for these productivity variables also tend to have a larger number of Ph.D.’s (see Appendix E).

Suggested Citation:"3 PAIRWISE CORRELATIONS." National Research Council. 2011. Research-Doctorate Programs in the Biomedical Sciences: Selected Findings from the NRC Assessment. Washington, DC: The National Academies Press. doi: 10.17226/13213.
×

This page intentionally left blank.

Suggested Citation:"3 PAIRWISE CORRELATIONS." National Research Council. 2011. Research-Doctorate Programs in the Biomedical Sciences: Selected Findings from the NRC Assessment. Washington, DC: The National Academies Press. doi: 10.17226/13213.
×
Page 17
Suggested Citation:"3 PAIRWISE CORRELATIONS." National Research Council. 2011. Research-Doctorate Programs in the Biomedical Sciences: Selected Findings from the NRC Assessment. Washington, DC: The National Academies Press. doi: 10.17226/13213.
×
Page 18
Suggested Citation:"3 PAIRWISE CORRELATIONS." National Research Council. 2011. Research-Doctorate Programs in the Biomedical Sciences: Selected Findings from the NRC Assessment. Washington, DC: The National Academies Press. doi: 10.17226/13213.
×
Page 19
Suggested Citation:"3 PAIRWISE CORRELATIONS." National Research Council. 2011. Research-Doctorate Programs in the Biomedical Sciences: Selected Findings from the NRC Assessment. Washington, DC: The National Academies Press. doi: 10.17226/13213.
×
Page 20
Suggested Citation:"3 PAIRWISE CORRELATIONS." National Research Council. 2011. Research-Doctorate Programs in the Biomedical Sciences: Selected Findings from the NRC Assessment. Washington, DC: The National Academies Press. doi: 10.17226/13213.
×
Page 21
Suggested Citation:"3 PAIRWISE CORRELATIONS." National Research Council. 2011. Research-Doctorate Programs in the Biomedical Sciences: Selected Findings from the NRC Assessment. Washington, DC: The National Academies Press. doi: 10.17226/13213.
×
Page 22
Next: 4 Time to Degree, Funding, and Completion Rates »
Research-Doctorate Programs in the Biomedical Sciences: Selected Findings from the NRC Assessment Get This Book
×
MyNAP members save 10% online.
Login or Register to save!
Download Free PDF

Research Doctorate Programs in the Biomedical Sciences: Selected Findings from the NRC Assessment examines data on the biomedical sciences programs to gather additional insight about the talent, training environment, outcomes, diversity, and international participation in the biomedical sciences workforce. This report supports an earlier publication, A Data-Based Assessment of Research-Doctorate Programs in the United States, which analyzes data and rankings from more than 5,000 doctoral programs, 982 of which were in the biomedical sciences. Research Doctorate Programs in the Biomedical Sciences explores questions about degrees and completion rates as they relate to GRE scores, student funding, program facilities, diversity among faculty members, and other variables. The report examines 11 biomedical science fields including cell and developmental biology, genetics and genomics, microbiology, nutrition, and physiology, among others.

  1. ×

    Welcome to OpenBook!

    You're looking at OpenBook, NAP.edu's online reading room since 1999. Based on feedback from you, our users, we've made some improvements that make it easier than ever to read thousands of publications on our website.

    Do you want to take a quick tour of the OpenBook's features?

    No Thanks Take a Tour »
  2. ×

    Show this book's table of contents, where you can jump to any chapter by name.

    « Back Next »
  3. ×

    ...or use these buttons to go back to the previous chapter or skip to the next one.

    « Back Next »
  4. ×

    Jump up to the previous page or down to the next one. Also, you can type in a page number and press Enter to go directly to that page in the book.

    « Back Next »
  5. ×

    Switch between the Original Pages, where you can read the report as it appeared in print, and Text Pages for the web version, where you can highlight and search the text.

    « Back Next »
  6. ×

    To search the entire text of this book, type in your search term here and press Enter.

    « Back Next »
  7. ×

    Share a link to this book page on your preferred social network or via email.

    « Back Next »
  8. ×

    View our suggested citation for this chapter.

    « Back Next »
  9. ×

    Ready to take your reading offline? Click here to buy this book in print or download it as a free PDF, if available.

    « Back Next »
Stay Connected!