Supporting Online Material for

Transcription

1 Supporting Online Material for The Two High-School Pillars Supporting College Science Philip M. Sadler* and Robert H. Tai *To whom correspondence should be addressed. This PDF file includes: Materials and Methods Tables S1 to S5 Published 27 July, Science 317, 457 (2007) DOI: /science

2 Supplementary Information Concerning Methods. Of the total, 31% of the sample were enrolled in biology, 42% in chemistry and 27% in physics. See Table S1. College Bio N = 2650 College Chem N = 3561 College Phys N = 2263 HS Course Level HS Bio HS Chem HS Phys HS Bio HS Chem HS Phys HS Bio HS Chem HS Phys none 0% 2% 16% 0% 1% 15% 1% 1% 13% Reg or Honors 83% 87% 77% 83% 79% 73% 86% 87% 78% AP 17% 12% 7% 16% 20% 12% 13% 12% 10% Table S1. Breakdown of Subjects by High School Preparation for Each College Science Course. The distribution of high school courses taken by students is remarkably similar across the three introductory college courses studied. More than 80% of college biology, chemistry or physics students had taken a regular or honors course in biology; only 15% had taken AP biology. Similarly, over 80% of our sample of college science students had taken a regular or honors course in chemistry, with 15% taking AP chemistry. High school physics enrollment followed with about three-quarters having taken a regular or honors physics course; only 10% had taken an AP physics course. Very few students did not take at least one year each of biology and chemistry in high school, while 15% did not take a high school physics course. High school course-taking was recoded into the equivalent number of years of high school exposure: regular or honors was coded as one year and AP was coded as two years. One AP course from among these three subjects was taken by 31% of students, 7% took two, and 1% took an AP course in each of the three sciences. Although some students enroll in an AP course without taking an earlier course in the same subject, this was a relatively rare occurrence. An AP science course is generally accepted as being a much more rigorous treatment of the subject matter than a regular or honors level course. Students in the original sample who were not included in the analysis represent a relatively small group. 4% were in non-u.s. countries for at least one year of high school. 1% were graduate students, and 4% were non-traditional (not enrolled in degree programs) We examined the possibility of non-linear effects of the number of years of a particular high school course using dummy variables for one and two years compared to a baseline of no study rather than employing a continuous variable. The Scheffe Post Hoc tests was employed to examine whether difference between number of years of high school science study of was significant at the p=0.05 level. There was no consistently non-linear effect seen across the different courses. We did not include high school grades in science as a predictor because students who did not take the subject in high school have no grades in the subject. This would also have eliminated those who did not take high school biology, chemistry, or physics, an important part of the sample.

3 College Biology College Chemistry College Physics Highest HS Math N = 2650 N = 3561 N = 2263 Algebra 2 or lower 19% 14% 13% Precalculus 45% 43% 39% Calculus 14% 15% 17% AP Calculus 22% 28% 31% Table S2. Breakdown by Highest Level of High School Mathematics for Each College Science Course. The distribution of the highest mathematics course taken in high school for each college level science course is reported in Table S2. Each level of mathematics commonly represents a year of high school study. One observes a clear difference between the math background of students taking college biology, chemistry and physics. Those in biology have a relatively weaker math preparation, with only 36% having had a calculus course in high school. Forty-three percent of college chemistry students and 48% of physics students had calculus in high school. Since each course in Table 2 generally represents a whole year of study, the mean number of years of high school mathematics study differs by 0.19 years for college chemistry over biology students and 0.08 years for college physics over chemistry students. The factors used to controlled for student background and their related statistics are shown for college biology (Table S3), college chemistry (Table S4), and college physics (Table S5). Year in college was significant only for biology and chemistry. Gender difference in grade were significant only for college physics. Parental and community education levels were significant for college biology and chemistry but not for physics. Race/Ethnicity was significant for each subject. Finally, high school preparation in biology, chemistry and physics was only found to be significant in that particular college course. There was no significant cross-disciplinary effect found. The regression coefficient for variables are presented in these tables. Standardized coeeficents (St. Beta) are calculated for continuous variables, The magnitudes of the intra-discipline coefficients are very similar, between 1.32 and 1.72 points in college grade for each year of the science subject in high school. The mathematics coefficients range between 1.28 and 1.84 and are significant in all three sciences. Standardized Betas are large for years of math study because there is a much wider distribution of number of years of high school mathematics than for any particular science subject.

4 College Biology Level of Const Coefficient std. err. prob St. Beta Constant Constant Š Race Asian/Pacific Islander Black Š Hispanic Multiracial other White Š Highest Parental Education ŠHS Some college year college Grad School Mean Ed Level of Community ML' SAT/ACT Exam Score Quantitative Š Verbal Š Last HS Grade in Math Š English Š College Year Freshman Sophomore Junior Senior Gender Female Years of HS Study Biology Chemistry Physics Mathematics Š Table S3. Additional Model Values for College Biology 0.17

5 College Chemistry Level of Const Coefficient std. err. prob St. Beta Constant Constant Š Race Asian/Pacific Islander Black Hispanic Š Multiracial other White Highest Parental Education ŠHS Some college year college Grad School Mean Ed Level of Community ML' SAT/ACT Exam Score Quantitative Š Verbal Last HS Grade in Math Š English Š College Year Freshman Sophomore Junior Senior Gender Female Years of HS Study Biology Chemistry Š Physics Mathematics Š Table S4. Additional Model Values for College Chemistry 0.17

6 College Physics Level of Const Coefficient std. err. prob St. Beta Constant Constant Š Race Asian/Pacific Islander Black Hispanic Multiracial other White Š Highest Parental Education ŠHS Some college year college Grad School Mean Ed Level of Community ML' SAT/ACT Exam Score Quantitative Š Verbal Last HS Grade in Math Š English Š College Year Freshman Sophomore Junior Senior Gender Female Š Years of HS Study Biology Chemistry Physics Mathematics Š Table S5. Additional Model Values for College Physics

7 Acknowledgements The authors would like to acknowledge the people who helped make this large research project possible: Janice M. Earle, Finbarr C. Sloane, and Larry E. Suter of the National Science Foundation for their insight and support; James H. Wandersee, Joel J. Mintzes, Lillian C, McDermott, Eric Mazur, Dudley R. Herschbach, Brian Alters, and Jason Wiles of the FICCS Advisory Board for their guidance; and Nancy Cianchetta, Susan Matthews, Dan Record, and Tim Reed of our High School Advisory Board for their time and wisdom. This research has resulted from the tireless efforts of many on our research team: Michael Filisky, Hal Coyle, Cynthia Crockett, Bruce Ward, Judith Peritz, Annettte Trenga, Freeman Deutsch, Nancy Cook, Zahra Hazari, Jamie Miller, Marc Schwartz, and Gerhard Sonnert. Matthew H. Schneps, Nancy Finkelstein, Alex Griswold, Tobias McElheny, Yael Bowman, and Alexia Prichard of our Science Media Group constructed of our dissemination website ( We also appreciate advice and interest from several colleagues in the field: Michael Neuschatz of the American Institute of Physics, William Lichten of Yale University, Trevor Packer of the College Board, Saul Geiser of University of California, Paul Hickman of Northeastern University, William Fitzsimmons, Marlyn McGrath Lewis, Georgene Herschbach, and Rory Browne of Harvard University, and Kristen Klopfenstein of Texas Christian University. We are indebted to the professors at universities and colleges nationwide who felt that this project was worth contributing a piece of their valuable class to administer our surveys and their students willingness to answer our questions.