Virginia M. Schelar, Roberf 0. Cluff, and Bernice Roth Northern Illinois University DeKolb, Illinois
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Placement in General Chemistry
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W i t h the increasing diversity of preparation-as well as the usual diversity of intellectual capacity-found among students entering the general chemistry course, placement has become essential. A three-year study has been conducted a t Korthern Illinois University to try to find a satisfactory method for placing students in Chemistry 210, a course primarily for chemistry majors and those whose future field of specialization requires rigorous preparation in chemistry. Chemistry 210-211 is a traditional year course including qualitative analysis in the second semester, Chemistry 211. The text used in 1960-1 was "General Chemistry, A Systematic Approach," second edition, by H. H. Sisler. C. A. Vanderwerf, and A. W. Davidson. Although the text was changed during the study, apparently this did not influence the results. The students used as subjects came from very diverse backgrounds: from large cities such as Chicago and from small farming communities. As the study progressed admission requirements to the University became more stringent. Enrollees in Chemistry 210 are required to have better preparation in mathematics than for the other beginning chemistry courses offered at Korthern Illinois University. On the hypothesis that students would benefit from being in classes where the abilities and preparation of other students are not too different from their own, the Office of Testing Services was requested to undertake a study of the marks earned by students in Chemistry 210 and the relationship of these marks to certain objective measures available for the students. For the purpose of the study it was assumed that ability in chemistry is measured by the mark in the course. The question was whether another criterion of this ability might be available prior to entrance in the course. A pilot study using entering freshmen taking Chemistry 210 in the fall of 1958 revealed that some of the objectme measures related to ability in chemistry were the score on a mathematics test, the total score on the scholastic ability test, and the reading comprehension score. It was decided to compute biserial r's using the criteria of "success" and "failure" as the arbitrary dichotomy. Success was defined as A or B; failure as For D. Relationships between marks in Chemistry 210 and objective test scores were studied relative to the entering freshmen in the fall of 1959 (see the table). Results indicated that the mathematics test score would have been the best criterion for placing the students studied. It seemed doubtful that any chemistry test Based on a. paper read before the Division of Chemical Education at the 144th Meeting of the American Chemical Society, Lw Angela, April, 1963.
per se could yield as high a correlation. Thus, the mathematics score was used the following year as an experimental criterion to divide Chemistry 210 courses roughly in half for sectioning purposes. I t was decided that the grade in the course mould be based primarily on the material common to the different sections. The higher level sections were enriched rather than accelerated. One of the authors constructed a trial test to see whether a snecific examination related to the skills commonly believed to be essential to success in beginning chemistry might prove better for placement of the students. The "Chemistry Placement Test"' consists of three parts: straightforward arithmetic problems and chemical problems stated as analogous everyday word problems; an intellectual ability part in which the student is called upon to read unfamiliar scientific material and answer questions about it; and a factual part based on recall of high school chemistry. The examination is entirely objective. The experimental chemistry placement test was given to all students in Chemistry 210 in the fall semester of 1960-61. The Office of Testing Services again correlated chemistry marks mith objective test scores available and with data from the chemistry placement test. The very high biserial correlation of the experimental chemistry test scores ( r b i . = 0.926) with the final grades in Chemistry 210 as compared to the correlation mith the mathematics scores, rhi. = 0.755 for the ACT Mathematics Standard Score, was sufficient encouragement to continue the study. 1 SCHELAE, V. M.: "Chemistry Placement Test," co?yrixbt 1963.
Biserial Correlations of Test Scores with Final Grades in First Semester Chemistrv 210 Tests Coop. Mathm SCAT Q" SCAT T" ACT Mathc ACT M'd CPTs
Correlations----196&61
195!?40 0.9314 0.81 0.6850
N
... ... ... =
83
0.731 0.559 0.83 0.755
N
0:626 = 115
1961-62 0.625 0.526 0.655 0.629 0.857 0.860 N = 124
a "Cooperative Mathematics Pretest for College Students," Form X, Cooperative Test Division, Educational Testing Service, Princeton, N. J., 1947. &SCAT("School and College Ability Tests"), Farm ,CI, Cooperative Test Division, Educational Testing Serwce, Pnneeton, N . J., 1957. eACT ("American College Test"), Iowa.City, Iowa, 1960. d ACT M': The predicted grade point average (GPA) in mathematics based on ACT Standard Test Scores and GPA's s t Northern. a CPT ("Chemistry Placement Test"), Virginia M. Schelar, 1963.
Volume 40, Number 7, July 1963
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369
In the fall of 1961 students were again placed in separate classes according to mathematics test score. One-third of the students were in upper sections and two-t,hirds in the lower. As a result of an item analysis the 'LChemistryPlacement Test" now had 43 five-item multiple choice questions chosen from the 66 in the experimental test. The table summarizes the findings in the three years the Chemistry 210 classes were studied. The type of sectioning done probably accounts for the instability of the SCAT predictive ability. Although the Cooperative Mathematics Test was the best predictor in 1959-GO, in 1960-1 it was next to the lowest. (In 19,5I)-60 no "Chemistry Placement Test" was given.) The ACT M' which was computed from the American College Test Prediction Equation for Mathematics is not a significantly better predictor of success in chemistry than the test results of any of the other tests evaluated. A related study (data not sho~vn)caused
370 / Journal of Chemical Education
the rejection of the hypothesis that there is a significant positive relationship between completion of high school chemistry and success in Chemistry 210 a t Sorthem Illinois University. There is little doubt that the ' Chemistry Placement Test" is a better instrument to use in placement a t Northern than any of the other data available. Both in 1961-2 and in 1960-1, its predictive ability was significantly higher than any of the other data available a t Northern. It is hoped that despite the local nature of the study, the results may be of value to others in plailning placement examinations. Xorthern Illinois University is a state supported school with an enrollment of approximately 8000. Further details may be obtained from the author. Grateful acknowledgment is made of the cooperation of five members of the Department of Chemistry who were a t various times engaged in teaching Chemistry 210 during the course of this studv.
