Full Terms & Conditions of access and use can be found at
http://www.tandfonline.com/action/journalInformation?journalCode=vjeb20
Download by: [Universitas Maritim Raja Ali Haji] Date: 11 January 2016, At: 22:12
Journal of Education for Business
ISSN: 0883-2323 (Print) 1940-3356 (Online) Journal homepage: http://www.tandfonline.com/loi/vjeb20
Documenting and Explaining Major Field Test
Results Among Undergraduate Students
Salvador Contreras , Frank Badua , Jiun Shiu Chen & Mitchell Adrian
To cite this article: Salvador Contreras , Frank Badua , Jiun Shiu Chen & Mitchell Adrian (2011) Documenting and Explaining Major Field Test Results Among Undergraduate Students, Journal of Education for Business, 86:2, 64-70, DOI: 10.1080/08832323.2010.480987
To link to this article: http://dx.doi.org/10.1080/08832323.2010.480987
Published online: 23 Dec 2010.
Submit your article to this journal
Article views: 42
View related articles
ISSN: 0883-2323
DOI: 10.1080/08832323.2010.480987
Documenting and Explaining Major Field Test
Results Among Undergraduate Students
Salvador Contreras
The University of Texas Pan American, Edinburg, Texas, USA
Frank Badua
Lamar University, Beaumont, Texas, USA
Jiun Shiu Chen and Mitchell Adrian
McNeese State University, Lake Charles, Louisiana, USA
The authors investigated the results of the Educational Testing Service Major Field Test (ETS-MFT) administered to business majors at a U.S. state university. Longitudinal trends and cross-sectional differences are documented, including significant performance differences among students of different majors. Findings suggest that a cohort affect may influence testing outcomes. The authors discuss with possible explanations for performance differences and explore means of remediation.
Keywords:assessment, business majors, ETS, MFT
INTRODUCTION
One question central to the task of business educators is, “Do different types of students retain the precepts of business edu-cation equally well?”The answer to this query may imply pro-found and pervasive ramifications to the curricula, policies, and practices of academia. Indeed, many accrediting organi-zations have made it an essential requirement of institutions seeking certification that they assess student learning and prove they are fulfilling their organizational missions (Bycio & Allen, 2007). In the case of business schools, this mission necessarily entails acquisition and postcompletion retention of business related knowledge and skills (Rudolph, 1981).In-stitutions of higher learning must assess student learning, an-alyze the results carefully, and continuously make program and content adjustments as necessary to achieve their aca-demic mission.
The authors wholeheartedly thank Ann L. Watkins for her inspiration, encouragement, and constructive critique, without which this article would not have been possible. We also thank McNeese University for its support. Any remaining errors are our own.
Correspondence should be addressed to Salvador Contreras, The Univer-sity of Texas Pan American, Department of Economics and Finance, 120 W. University Drive, Edinburg, TX 78539, USA. E-mail: contrerass@utpa.edu
In addition to the basic assumptions of program suffi-ciency, the analysis of student learning should include a consideration of various factors that impinge on the abil-ity of a student to absorb the necessary information. The present study extends previous research such as that by Allen and Bycio (1997), Bycio and Allen (2007), and De Mong, Lindgren, and Perry (1994) to examine the affects of demo-graphic and academic variables on student test performance. Findings suggest a possible cohort affect on student perfor-mance and recommendations are made for remediation of student learning and for future research.
Objective
We explore the effects of age, gender, ethnicity, and aca-demic background on student testing performance. Previous researchers (Allen & Bycio,1997) examined the impact of demographic variables on test results on the Major Field Test (MFT), an exam used to test for retention of basic business knowledge among business school students, but results were mixed. We included an investigation of the differential ef-fects of various explanatory factors on cohorts comprising different majors. Major affiliation has been correlated with academic performance, including traits such as effort toler-ance and effort aversion. Major affiliation was also deployed
A MAJOR DIFFERENCE 65
as an explicator of the absorption of the principles of a busi-ness curriculum but the cohort effects have hitherto not been investigated.
Research Questions
Pursuing this endeavor, the overall question of demographic affect on student performance was refined by asking the fol-lowing questions.
Research Question 1:Do students of different demographic backgrounds, such as different genders, ages, and eth-nicities, perform differently on the MFT?
Research Question 2:Do students in different majors perform differently on the MFT?
Research Question 3:Do students with different academic histories as captured by GPA and ACT score perform differently on the MFT?
With these questions in mind, this research attempts to measure the impact of various demographic and academic factors on acquisition and retention of general business knowledge as measured through the MFT. The sample tracks student performance between 2005 and 2007 on the MFT exam administered at a U.S. state university over that period. Systematic differences in test performance between students from different business majors are identified, and based on these, a number of possible program- and student-specific ex-planations for these differences are concluded. These include differences in past academic aptitude, as measured through ACT scores and GPA, program-specific characteristics, as proxied by major dummies, and other student-specific char-acteristics. Various means of improving test outcomes are briefly considered as well.
MFT Background
The MFT is administered by the Educational Testing Ser-vice (ETS) as a program specific assessment tool for un-dergraduate and MBA students. The test may be configured to comprehensively assess knowledge in biology, chemistry, computer science, criminal justice, economics, education, history, English literature, mathematics, music, physics, po-litical science, psychology, and sociology, as well as Asso-ciate’s, Bachelor’s, and Master’s programs in Business. The MFT has been adopted by some 700 colleges and universities worldwide.
The test is typically administered to students at the com-pletion of their program of study, usually in the final year of coursework. The content of the MFT is based on core cur-ricula of the assessed programs, as identified by nationwide surveys of educational institutions. The test results that in-form this research are from the MFT exam administered to Bachelor’s degree candidates in business. The MFT in busi-ness comprises some 120 questions based on curricula of several business related subject areas. The typical business
administration MFT consists of questions from accounting (16%), economics (16%), management (17%), quantitative methods (16%), finance (12%), marketing (12%), business law (10%), and international business (1%).
Test results are intended to measure basic knowledge from a broad array of business disciplines, rather than advanced or specialized knowledge in a specific business major. For this reason, the MFT is often used to assess the effectiveness of business schools, particularly those seeking accreditation with the Association to Advance Collegiate Schools of Busi-ness (AACSB), and other similar accrediting bodies (Bycio & Allen, 2007).
Related Literature
This research contributes to a small but varied body of lit-erature that investigates phenomena related to standardized testing of business students. Most of this literature studies alternatives to optimize the assessment of learning in busi-ness programs (Bogue & Saunders, 1992; De Mong et al., 1994; Ebel & Frisbee, 1986; Erwin, 1991; Ewell, 1987, 1988; Ferris, 1982; Herring & Izard, 1992; Herring, Scheiner, & Williams, 1989; Hutchings & Marchese, 1990; Hutchings, Marchese, & Wright, 1991; Milton, Pollio, & Eison, 1986; Palomba & Banta, 1999; Paskow & Francis, 1990; Phillipi, 1989; Spangehl, 1987; Terenzini, 1989).
A smaller branch of the research stream studies different factors that affect student performance on standardized tests (Allen & Bycio, 1997; Buckless, Lipe, & Ravenscroft, 1991; Bycio & Allen, 2007; Dunn & Hall, 1984, 1988; Loewen, Roessen, & Katzman, 1988). This study adds to the sec-ond group of works, which investigates performance and its determinants.
Although previous literature has provided a wealth of in-formation regarding student characteristics that play a part in performance on standardized tests, such as gender (Buckless et al., 1991; Loewen et al., 1988), and curricular grades (Allen & Bycio, 1997; Bycio & Allen, 2007), this study makes a number of additional contributions to the existing research. Specifically, the work of Bycio and Allen (2007) is extended by including major dummy variables and by estimating re-gression models by major cohort. Findings by Bycio and Allen (2007) and De Mong et al. (1994) demonstrating that academic aptitude has a significant impact on how students perform on the MFT are also supported.
METHOD
Unit of Study
The unit of study in this research is the results of business administration MFTs administered to students at the college of business of a U.S. state university. The test was admin-istered two times per year, in the spring and fall semesters, from fall 2005 to spring 2008.The results for six distinct test
FIGURE 1 Drop-line analysis of MFT results, by major.
dates were generated, specifically: fall 2005, spring 2006, fall 2006, spring 2007, fall 2007, and spring 2008. A total of 352 student test results were recorded.
Preliminary Analysis
In order to quickly characterize the MFT score distribution and identify any patterns, regularities, and tendencies therein, an Exploratory Data Analysis (EDA) technique, drop line analysis, was used.
The average test score for all test dates was 149.44 (SD=
12.4) out of 200. The highest individual student score was 192, and the lowest was 123. The average score has fluc-tuated from a high of 151.35 (SD = 12.1) in spring 2006 to a low of 146.8 (SD =14.0) in fall 2006; however, av-erage scores have clustered in the range between 148 and 150. This is consistent with the average student test score of 149.44.
A cross-sectional analysis of the MFT results revealed what appears to be a systematic variation in test outcomes based on student major.
Figure 1 plots average MFT scores by date and major. The test score ranges of each major are quite different from one another. Accounting majors had a high score of 154.88 (spring 2006) and a low score of 149.38 (fall 2006). Finance majors achieved a high score of 158.5 (fall 2006) and low score of 144.9 (spring 2008). On the other hand, high–low spreads for general business (154.25 in spring 2007, 142.71 in fall 2007), management (148.46 in spring 2007, 140.45 in fall 2006), and marketing (151.25 in spring 2008, 144.17 in fall 2006) were generally lower than those of the two aforementioned majors. Therefore, the initial EDA results indicate systematic differences in MFT performance between students of different majors.
Regression Analysis
In order to further test the apparent impact of major on test performance, a regression model with MFT performance as the dependent variable and major dummies of age, gender, race, total GPA, and total score on the American Collegiate Test (ACT) as independent variables, was estimated. The specifications of this model capture differences in perfor-mance by students of different majors, the influence of demo-graphic factors, and curricular learning and initial academic aptitude(as proxied by both total GPA and ACT score, respec-tively). Asis discussed subsequently, previous researchers such as Bycio and Allen (2007) and De Mong et al. (1994) used GPA and ACT score as proxies for students’ general business knowledge, and general test-taking ability, or gen-eral intellect, so that these are arguably measures for the effect of the program and instruction and initial academic aptitude, respectively.
The model was specified as MFT=f (ACCT, FIN, MGNT, MRKG, AGE, MALE, WHITE, BLACK, GPA AVG, ACT COMP)where
• MFT=performance on the MFT, measured as four ordi-nal values, where if the score was in the 90th percentile the student received a score of 4, in the 80th percentile the student received a 3, in the70th percentile the student re-ceived a 2, and in the 60th percentile the student rere-ceived a 1.
• ACCT, FIN, MGMT, MRKG=dummies for student
ma-jor
• AGE=student age at exam date
• MALE=dummy for gender
• WHITE, BLACK=dummies for race; it should be noted that the population of the study was largely white (276 of 357 participants).
• GPA AVG=student GPA for all undergraduate courses, capturing four semesters of data, including the semester that the exam was taken, except for all courses dropped and nongrade (pass/fail) courses, which were omitted.
• ACT COMP=student score on the ACT
Regression results from this model (Table 1, column 1) reveal significant negative correlations between performance on the MFT and being an accounting major (r= −.34,p<
.01), management major (r= −.31,p<. 05), and marketing
major (r= −.37,p<.01). The influence of being a finance
major was not significant (r=.14). The general business ma-jor dummy variable was dropped to avoid multicollinearity (the general business degree contains an even mix of course-work from all the other previously mentioned majors).
Of the demographic variables, age (r = .03 p < .01)
and being a man(r =.18, p<.05) were significantly and
positively correlated with better performance on the MFT. Finally, total GPA (r=.24,p<.01) and ACT score (r=.09,
p<.01) were both found to be positively and significantly
correlated with MFT performance.
A MAJOR DIFFERENCE 67 TABLE 1
Regression Results for MFT Full Sample (1) and by Major Cohort (2–6)
(1) (2) (3) (4) (5) (6)
Variable Full sample Accounting Finance Management Marketing General business ACCT −0.34∗∗∗
∗=90% significance;∗∗=95% significance;∗∗∗=99% significance.
To further investigate major specific performance differ-ences, the following model was estimated separately for
each major: MFT = f (AGE, MALE, WHITE, BLACK,
GPA AVG, ACT COMP).All of the variables in this model were the same as in the original model, but major dummy variables were dropped. The objective of this series of regressions was to identify any differences in the influence of demographic and academic predictors on MFT performance and see if these differed among majors.
The results of these regressions by each major cohort are shown in Table 1, columns 2 to 6. Among accounting ma-jors, it was found that only one demographic explanatory variable, AGE, was significant (r=.03, p<.01) and had
a positive correlation with test performance. Both academic predictors, GPA AVG (r=.33,p<.05) and ACT COMP
(r = .09, p< .01), were positively correlated with
perfor-mance and significant. Thus, of the two academic explana-tory variables, the accounting student’s academic aptitude throughout the undergraduate business program was both a stronger and more significant predictor than the initial aca-demic aptitude.
For finance majors, only one predictor variable, ACT COMP (r=.09, p <.05) was significant, and as in
the original model, was positively correlated with test per-formance. The other academic explanatory variable, GPA score, was not significant, although still positively associ-ated with performance. None of the demographic variables were significant.
Management majors’ MFT performance was positively and significantly correlated with both academic predictors, but GPA was a stronger and more significant explicator (r =.29, p<.05) than ACT score (r =.07, p<.01). As
with accounting, GPA was the stronger predictor of the two academic explanatory variables. None of the demographic variables were significant.
Marketing major test performance was significantly and positively correlated with being a man (r=.38, p<.05) and
with ACT score (r=.09,p<.01), whereas none of the other
variables was significant. Finally, only ACT score (r=.09,
p<.01) was a significant predictor among general business
majors.
DISCUSSION
Table 2 summarizes this study’s research questions and the relevant findings. Statistical results pertaining to these re-search questions are also included.
The first research question (Research Question 1) per-tained to whether students of different demographic back-grounds, such as different genders, ages, and ethnicities, would perform differently on the MFT. Results from both the full-sample and major cohort regressions models indicated that there were significant differences in performance be-tween students of different demographic types. Specifically, the full-sample model showed that older students and male students did better on the MFT. Furthermore, the account-ing cohort and marketaccount-ing cohort models showed that older students and male students performed better on the MFT, respectively. Hence, Research Question 1 was answered in the affirmative.
The second research question (Research Question 2) per-tained to whether students in different majors would perform differently on the MFT. Results from the full-sample re-gression indicated that there were such differences in MFT performance between students of different majors. The re-gression revealed that being an accounting, management, or marketing major is negatively associated with performance on the MFT, a finding that is discussed further in the con-clusion. Thus, Research Question2 was also answered in the affirmative.
TABLE 2
Summary of Research Questions and Findings
Answer
Applicable explanatory variable (coefficient, significance)
Research Question 1 Do students of different demographic backgrounds, such as different genders, ages, and ethnicities perform differently on the MFT?
Yes Full Sample Age (.03, 99%); ACCT Cohort Age (.03, 99%); Full Sample Male (.18, 95%); MKTG Cohort Male (.38, 95%)
Research Question 2 Do students in different majors perform differently on the MFT?
Yes ACCT Sample GPA (.33, 95%); MGMT Sample GPA (.31, 95%); Full Sample Major Dummy for ACCT (−.34, 99%), MGMT (−.31, 95%), MKTG (−.37, 99%)
Research Question 3 Do students with different academic histories as captured by GPA and ACT score perform differently on the MFT?
Yes All Samples ACT (avg.=.09, min.=95%); Full Sample GPA (.24, 99%), ACCT Sample GPA (.33, 95%); MGMT Sample GPA (.31, 95%)
The third research question (Research Question3) per-tained to whether students with different academic histories, as reflected in their GPA and ACT score, would perform differently on the MFT. Once again, results from both the full-sample and major cohort regressions indicated the pres-ence of such differpres-ences. The full-sample, accounting major cohort, and the management major cohort regressions all showed that students with higher GPAs performed better on the MFT. Moreover, all five major cohort regressions revealed that students with higher ACT scores performed better on the MFT as well. Whereas Bycio and Allen (2007) did not utilize the same controls used in this study, these results support the previous finding that both GPA and ACT score had a sig-nificant impact at predicting a student’s MFT performance. Therefore, Research Question 3 was answered affirmatively.
Summary and Implications
In conclusion, this study contributes to existing literature on standardized test performance by business majors, con-firming previous findings that innate characteristics have a significant impact on how students perform on the MFT. Specifically, it is shown that test results may be affected by academic and demographic factors as well as by students’ academic major.
The demographic variables age and gender are signif-icant factors in predicting MFT performance, with older students and male students performing better on the test. However, while the full sample regression results confirm earlier EDA findings for management and marketing majors, whose choice of major is negatively associated with MFT performance, the results contradict the initial analysis as re-gards accounting and finance. EDA indicated that being an accounting or finance major would be associated with bet-ter performance on the MFT, but the regression shows that being an accounting major was a predictor of poor perfor-mance, and being a finance major did not have any significant influence at all.
The results of the major cohort model regressions may explain the apparent contradiction regarding accounting ma-jors. In the accounting major cohort regression, the stu-dent’s GPA was significantly and positively correlated with MFT performance, a result that only management majors replicated. This may mean that though being an accounting major per se negatively correlates with MFT performance, doing well as an accounting major correlates with doing well on the test, a result that is not found among finance, marketing, and general business majors. In the cases of ac-counting and management, this finding may imply that the accounting and management curricula may have provided students with a broader exposure to business knowledge that prepares them significantly better for the MFT than other programs.
Alternatively, it is a possibility that accountancy and man-agement differ from other majors in the manner and rigor of student performance evaluation in these courses. Indeed, the findings of the second model, which separately regressed MFT performance on the predictors for each major cohort, support this assertion, as may be seen in the differences in the magnitude and significance of academic explanatory variables.
The nature of the findings suggests several implica-tions for academia, including recommendaimplica-tions for ad-ministrators to correct inequities and suboptimalities that result from factors such as demographic background and initial academic aptitude. In addition, these findings are suggestive of a reexamination of the present curriculum, course content, and pedagogical practices. These implica-tions and the resulting policy recommendaimplica-tions as well as avenues for future researchers are discussed in the following sections.
Policy Recommendations
Having documented specific patterns of differential perfor-mance and identified possible explanations for these, we con-clude with some possible means of ameliorating performance
A MAJOR DIFFERENCE 69
for those student groups that need improvement. The find-ings about demographic predictors lead to mixed conclusions about the effectiveness of academia’s efforts at creating a nurturing and welcoming environment for nontraditional stu-dents. Although older students are shown to do better on the MFT, being a male student also correlates positively with per-formance on the exam. These results, pertaining to Research Question1, may hopefully help refine future initiatives at de-veloping effective academic programs for a diverse student body.
Although it is true that theoretically, no single business major curriculum could provide a greater amount of knowl-edge relevant to the test than other majors because of the way the MFT is structured, it is possible that other factors in-trinsic to these majors may be responsible. It is possible that students in some majors are better accustomed to test taking, and the attendant tasks of information retention, analysis, and computation, than those of other majors. If major specific dif-ferences are indeed a factor, it may help to standardize prac-tices and rigor across majors in order to ensure all students are developing retentive, analytical, and quantitative skills, regardless of major. If, on the other hand, major affiliation is systematically explained by initial academic aptitude, and differential test performance between majors is ultimately caused by these student-specific qualities, this suggests that changes in the recruitment and student advising processes are necessary to ensure that all majors attract the best possible degree candidates.
Further Research
Although we identified several significant determinants of business student performance on the MFT, other factors, not captured in the data used, could also be relevant. These factors could be student-, major-, or institution-specific. Thus, fur-ther research is necessary to specifically investigate whefur-ther these major differences arise from the curricula offered or by self-selection of certain types of students into certain ma-jors, as well as how robust results would be across various colleges or universities.
Of student specific characteristics, previous research has identified self-selection and motivation factors, and the ef-fects of different levels of self-efficacy. Nevertheless, we did not directly test for the presence or effect of these differences, so further research is necessary for more conclusive results. This further research would be best served by data that was not available for this research, such as surveys of student attitudes or appropriate proxies thereof.
Differences in course of study may be of two types, dif-ferences in topical coverage, and difdif-ferences in pedagogical technique. Topical differences among the various majors, theoretically, would not be a factor because of the structure of the MFT, which is intended to measure general business knowledge, rather than discipline specific learning. However, to the extent that concepts originating in specific disciplines,
such as cost-benefit analysis or asset and resource valua-tion, are relevant across programs, mastery of the mother discipline may have a disproportionately high effect on test performance. Similarly, while the actual topics may not be relevant predictors of MFT performance, the type of ques-tions, problems, or learning tasks prevalent in a particular discipline may better prepare students for the test than those of other programs. Further research would be needed to more precisely determine the effects of these curricular variables on student performance.
A final avenue of further research stems from the fact that the data in this research is limited to one institution, a state university in the southern United States. Other research cited in this study also had samples similarly limited to individual institutions or individual states such as Illinois (Buehlmann, 1975), Ohio (Bycio & Allen, 2007), Texas (Dunn & Hall, 1984), Tennessee (Herring & Izard, 1992), Iowa (Ingram & Petersen, 1987), and Florida (McCormick & Montgomery, 1974). Therefore, further research would be most helpful if it expanded the sample size to include a variety of institutions from different regions.
REFERENCES
Allen, J. S., & Bycio, P. (1997). An evaluation of the educational testing service major field achievement test in business.Journal of Accounting Education,15, 503–514.
Bogue, E. G., & Saunders, R. L. (1992).The evidence for quality. San Francisco, CA: Jossey-Bass.
Buckless, F. A., Lipe, M .G., & Ravenscroft, S. P. (1991). Do gender effects an accounting course performance persist after controlling for general academic aptitude?Issues in Accounting Education,6, 248–258. Buehlmann, D. (1975). ISU’s use of the AICPA college testing program.
Journal of Accountancy,LXII, 93–96.
Bycio, P., & Allen, J. S. (2007). Factors associated with performance on the educational testing service major field achievement test in business.
Journal of Educational for Business,82, 196–201.
De Mong, R. F., Lindgren, J. H., & Perry, S. E. (1994). Designing an assessment program for accounting.Issues in Accounting Education,
9(1),11–27.
Dunn, W., & Hall, T. (1984). An empirical analysis of the relationship be-tween CPA examination candidate attributes and candidate performance.
The Accounting Review,59, 674–689.
Dunn, W., & Hall, T. (1988). How effective are accounting programs? To-day’s CPA, March–April, 29–34.
Ebel, R., & Frisbee, D. (1986).Essentials of education measurement. En-glewood Cliffs, NJ: Prentice Hall.
Erwin, T. (1991).Assessingstudent learning and development. San Fran-cisco, CA: Jossey-Bass.
Ewell, P. T. (1987). Assessment: Where are we?Change,19, 23–28. Ewell, P. T. (1988). Implementing assessment: Some organizational issues.
New Directions for Institutional Research,59, 15–28.
Ferris, K. (1982). Educational predictors of professional pay and perfor-mance.Accounting Organizations and Society,7, 225–230.
Herring, H. C., & Izard, C. D. (1992). Outcomes assessment of accounting majors.Issues in Accounting Education,7(1), 1–17.
Herring, H. C., Scheiner, J. H., & Williams, J. R. (1989). The development of education research in accounting.Issues in Accounting Education,4(1), 48–56.
Hutchings, P., & Marchese, T. (1990). Watching assessment: Questions, stories, prospects.Change,22, 13–38.
Hutchings, P., Marchese, T., & Wright, B. (1991).Using assessment to strengthen general education. Washington, DC: American Association for Higher Education.
Loewen, J. W., Roessen, P., & Katzman, J. (1988).Gender bias in SAT items. EDRS Document ED 294 915, Annual Meeting of the American Educational Research Association, New Orleans.
McCormick, R., & Montgomery, J. (1974, April). The use of AICPA tests in evaluating transfer students at a university.Journal of Accountancy, August, 82–88.
Milton, O., Pollio, H., & Eison, J. (1986).Making sense of good college grades. San Francisco, CA: Jossey-Bass.
Palomba, C. A., & Banta, T. W. (1999).Assessment essentials, planning, implementing, and improving assessment in higher education. San Fran-cisco, CA: Jossey-Bass.
Paskow, J., & Francis, E. A. (1990).Assessment programs and projects: A directory. Washington, DC: American Association for Higher Education.
Phillipi, R. (1989).Instructional evaluation data. Knoxville, TN: The Center for Assessment Research and Development, University of Tennessee. Rudolph, B. (1981). Conceptualization vs. vocationalism.Journal of
Mar-keting Education,3(2), 23–27.
Spangehl, S. (1987). The push to assess.Change,19, 35–39.
Terenzini, P. T. (1989). Assessment with open eyes: Pitfalls in studying student outcomes.Journal of Higher Education,60, 644–665.
