CEE 101 Back to Evaluation and Assessment

*Instructor comment: Grade inflation is not limited to adjunct instructors however, this article raises several good and interesting points that you should be aware of.

Journal of Education for Business, Sept 2000 v76 i1 p5
A Is for "Adjunct": Examining Grade Inflation in Higher Education. (Statistical Data Included) BRENDA S. SONNER.
Full Text: COPYRIGHT 2000 Heldref Publications

ABSTRACT. Though grade inflation is hardly a new problem, it may be worsening as universities increase their reliance on temporary, part-time instructors. Adjunct instructors, hired on a term-by-term basis, are easily replaced; thus, most face serious pressure to earn good evaluations from students. Keeping students happy may mean giving higher, potentially inflated, grades. This study explicitly compared the average class grade given by adjunct instructors and full-time faculty over a 2-year period at a small public university. The results suggest that adjunct instructors do give higher grades than do full-time faculty.

There is little debate that grade inflation is a serious issue in higher education. A recent article by scholars at Princeton University (Farley, 1995) cited research finding that only 10% to 20% of all college students receive grades lower than B-. This means, of course, that between 80% and 90% of all college students receive grades of either A or B!

Several studies have shown that student grades are related to instructor rank (Ford, Puckett, & Tucker 1987; Jackson, 1986; Sonner & Sharland, 1993; Williamson & Pier, 1985). Research on this issue has shown consistently that lower ranking faculty give much higher grades than do senior faculty. Studies that have examined grading differences, however, have either focused on comparing graduate teaching assistants with full-time faculty (Ford, Puckett, & Tucker, 1987; Sonner & Sharland, 1993; Williamson & Pier, 1985), or have been conducted at community colleges, which traditionally rely heavily on adjunct instructors (Jackson, 1986).

Although community colleges continue to rely heavily on adjunct instructors, use of such temporary, part-time teachers is no longer confined to community colleges. As operating costs have increased, more and more universities have turned to adjunct faculty. A recent study reported that hiring patterns have shifted to the point where more than 40% of university faculty are part-time (Leslie, 1998). In fact, between 1976 and 1995, the number of part-time faculty increased by 91%, compared with an increase of only 27% in the number of full-time faculty (Clery, 1998).

It should not be surprising that universities are increasingly turning to adjunct faculty (Grenzke, 1998). Adjuncts can be terminated at any time, giving universities flexibility when enrollments decline. Many adjuncts have considerable real-world experience in their fields and are able to offer students a perspective that may be different from that of teachers who do not work in the field (Thompson, 1984).

As the use of adjunct instructors increases, however, the question that many universities must address is whether it is fueling grade inflation. My research compares grades given by adjuncts with grades given by full-time faculty at a small public university over a 2-year period. If, within a single university population, grades given by adjunct faculty members are higher than those given by full-time faculty, administrators must be prepared to address the issue.

Several studies have attempted to examine the quality of instruction provided by adjuncts, but much of the research has been based on comparisons of student or administrator evaluations. Grenzke (1998) reported that adjuncts are more likely to be evaluated than are full-time faculty; however, in general, students do not rate adjuncts as highly as full-time faculty (Jackson, 1986). Full-time faculty are rated higher on knowledge of the subject, presentation of the material, and other key issues (Jackson, 1986). In addition, the studies suggest that adjuncts are not as actively involved in scholarship, knowledge acquisition, or professional development (Clery, 1998; Freeland, 1998; Rifkin, 1998) and feel less responsibility and obligation to maintain academic integrity in the classroom (Freeland 1998; Rifkin, 1998).

A few studies have explicitly examined the teaching proficiency of adjuncts. In one study (Clark, 1990), scores on a standardized final exam were compared for differences between students who had adjuncts as instructors and students who had full-time faculty as instructors. The final exam scores were found to be identical for the two groups. Bolge (1995) conducted a pre- and posttest of basic mathematics students and also concluded that there was no difference between the performance of students who were taught by adjunct faculty and the performance of those who were taught by full-time faculty.

The evidence suggests that part-time adjunct instructors are comparable in their teaching abilities to full-time faculty members. In fact, several studies have concluded that adjuncts are committed to teaching (Freeland, 1998) and have high expectations of their students (Freeland, 1998; Rifkin, 1998). If adjuncts and full-time faculty are comparable in their teaching abilities, it would seem reasonable to assume that the grades given would be comparable. This study tests the following hypothesis:

H: There is no difference in the average grade awarded by part-time (adjunct) faculty and full-time faculty.

If, however, evidence is found suggesting that adjunct instructors give students higher grades than full-time faculty, it would suggest that the adjuncts are inflating student grades. In that case, higher grades in courses taught by adjunct instructors would lead students to develop unrealistic expectations about the grades they should receive (Landrum, 1999) and lead to pressure on full-time faculty to follow, or risk student outcry and poor evaluations.


The data for this study were provided by a small public university that is an ideal environment for the study because it relies heavily on adjunct faculty. In a typical term, for example, approximately 30% of the classes are taught by fulltime faculty and approximately 70% are taught by adjunct faculty. Most adjuncts teach two classes per term, and many are highly experienced, having been teaching for several years.

Every business class taught during a 2-year (8-quarter) period was included in the analyses, for a total of 395 classes. In each class, the number of A, B, C, D, and F grades was used to calculate the average grade in a particular class. A 5-point scale ranging through 4 (A), 3 (B), 2 (C), 1 (D), and 0 (F) was used to calculate the average grade, which could range from 4.0 (for a class in which every student received an A) to 0 (for a class in which every student received an F).

There are numerous factors that may affect the average grade given in a particular class. In this study, four potentially biasing factors are examined: class size, instructor credentials, subject, and course level. I examined each of the factors separately through ANOVA and included only those factors that were related to the average class grade as covariates in the final analysis (ANCOVA). Including these factors as covariates controlled for any biasing effects caused by them while testing the main relationship, a comparison of grades given by full-time and adjunct faculty.


In the sample, 37% of the classes were taught by full-time faculty and 63% were taught by adjunct faculty during the 2-year period. A total of 7,610 grades were awarded.

Most of the students were given grades of A or B, and less than 20% of the students were given grades below C (see Table 1). The average grade for all of the students was 2.7, approximately a B- or C+. This average, though slightly higher than the traditionally accepted average of 2.5, is consistent with the findings of other studies (Summerville, 1988).

TABLE 1. Grades Earned by All Students, in Percentages

Grade % of students

A 28.3
B 31.8
C 21.5
D 9.1
F 9.3

A preliminary analysis showed that the average class grade in courses taught by adjuncts was higher than that in courses taught by full-time instructors. The average grade given by fulltime faculty was a 2.6, compared with an average grade of 2.8 by adjuncts. Though the difference seems small, it is large enough to be statistically significant (F = 16.41, p [is less than] .000).

Class Size

One factor that could potentially affect grades is the total number of students in a class. In smaller classes, instructors have a greater opportunity to get to know the students, and when instructors have greater knowledge about a student's level of effort they may tend to be more lenient. Simply having a closer working relationship may make the instructor less likely to give a "bad" grade for fear of upsetting the student. Smaller classes at the end of the term may also be the result of weaker, less-prepared students dropping the class before the end of the term.

In this data set, there was a negative correlation between class size and average class grade. The fewer students in a class, the higher the average class grade (r = -.0995, p [is less than] .048). This variable was included in the final analysis to control for any bias resulting from class size.

Instructor Credentials

Another potential source of bias is the training and credentials of the instructor. Instructors with a terminal degree (PhD, DBA, JD in law courses) may have greater knowledge of the subject and for that reason may set higher standards for their students. If that is the case, average class grades should be lower for courses taught by instructors with terminal degrees.

Although adjuncts typically do not hold terminal degrees, in this particular situation, many did. In this data set, 29% of the classes were taught by adjunct faculty holding terminal degrees.

The average grade in classes taught by instructors with a terminal degree was 2.7, whereas the average grade in classes taught by instructors with only a master's degree was 2.8. This difference, though in the expected direction, was not large enough to be statistically significant (F = 1.473, p [is less than] .226). The credentials of the instructor did not affect the final class grade, and this variable was not included in the finalanalysis.


A business education requires students to take classes in a variety of subjects, some of which have a reputation for being more difficult than others. For example, students generally fear classes in statistics and economics and other quantitative classes (Clusky, 1997). Indeed, the lowest grades at this university are given in the quantitative methods (average = 2.40) and economics classes (average = 2.28), whereas the highest grades are given in marketing (average = 3.34) and management (average = 3.01). Given the differences between the average grades in the various disciplines (F = 20.343, p [is less than] .00), this variable was included as a covariate in the final analysis.

Course Level

Another potentially biasing factor is the level of the course. Lower level courses (100 and 200 level classes) may have a greater number of weaker students who will not be able to progress to the upper level courses. In addition, the junior level classes (300 level), which include the introductory, core classes in most of the business disciplines, may have a large number of students who have neither skill nor an interest in the particular subject. Senior level courses (400 level) generally include elective courses in the student's major area. These courses may have higher average class grades simply because students are more interested in the classes.

There was a difference in the average class grades for the various class levels (F = 55.831, p [is less than] .00). As expected, senior classes (400 level) had the highest average class grade (average = 3.21), followed by the junior classes (300 level, average = 2.87). Sophomore and freshman level classes had the lowest average grades (200 level, average = 2.38; 100 level, average = 2.65). Given these differences, this variable was included in the final analysis.

Comparison of Grades Given by Full-Time and Adjunct Faculty

The results of these preliminary analyses indicated that three factors were related to the average class grade: class size, subject, and class level. A comparison of the average class grades given by full-time and adjunct business faculty, after controlling for these three factors, indicates that there is still a difference in the grades given by these two groups of instructors (F = 23.07, p [is less than] .000). Grades given by adjunct faculty tend to be higher even when the other, potentially biasing factors are controlled.

Discussion and Implications This research indicates that differences exist between the grades given by adjuncts and the grades given by full-time faculty. Even after controlling for the impact of other factors that could explain the differences, grades tend to be higher in classes taught by adjunct faculty.

There are several possible explanations for this, though most are hardly plausible. For example, though it could be argued that adjunct faculty simply teach "better" students, this explanation is hardly credible. These data were taken from a single student population; thus, both full-time and adjunct faculty were teaching the same students. It could also be argued that adjuncts are better teachers and, because of that, students perform better in their classes. Though that may be true for some adjuncts, there were over 40 different adjunct faculty members in this data set. It seems highly unlikely that such a large and diverse group would all be better teachers.

From this analysis, the most likely explanation is that adjunct faculty give higher grades for comparable work than do full-time faculty. It seems reasonable to conclude that adjunct faculty, who are employed on a term-by-term basis, are hesitant to give lower grades as it could create student complaints that would result in the adjunct not receiving an offer to teach in subsequent quarters.

It is clear from these analyses that increased use of temporary, part-time instructors may result in even greater grade inflation. In addition to the direct impact of the higher grades, the situation increases pressure on the full-time faculty to give higher grades if students come to expect them.

The potential for grade inflation is an issue that needs to be monitored and evaluated by university administrators. At the very least, adjunct faculty must receive training and support from the university to abide by grading standards that are consistent with those of the fulltime faculty.


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BRENDA S. SONNER Troy State University-Montgomery Montgomery, Alabama