Previous studies have identified a number of factors that contribute to the retention of undergraduates in 4-year colleges and universities in general (see for example Nora, Barlow, & Crisp, 2005; Tinto, 1993; Titus, 2004, 2006) and STEM fields in particular (Daempfle, 2003; Elliott, Strenta, Adair, Matier, & Scott, 1996; Grandy, 1998; Seymour & Hewitt, 1997; White, Altschuld, & Lee, 2006). Some of the factors that have been shown to contribute to STEM retention include students' high school academic preparation (Elliott et al., 1996), freshmen academic performance and enrollment in “gatekeeper” courses (Crisp, Nora, & Taggart, 2009), personal contact with faculty (Daempfle, 2003), degree of racial isolation (Seymour & Hewitt, 1997), exposure to racial minority support systems (Grandy, 1998), and an institution's level of selectivity (Chang, Cerna, Han, & Sáenz, 2008; Chang et al., 2011; Espinosa, 2011). Taken together, these studies suggest that completion of a STEM degree requires not only academic preparation but also resilience and capacity to negotiate a complex academic context.
Key Individual Experiences and Institutional Factors
For URM students who pursue undergraduate studies in STEM fields, a combination of environmental and internal psychological factors has been shown to impact persistence. For example, Elliott et al. (1996) found that African American students had far less preparation in pre-college sciences, as demonstrated by lower rates of participating in AP Biology, Chemistry, Physics, and Calculus courses. As Russell and Atwater (2005) noted, a demonstrated competence in science and mathematics at the pre-college level is vital to African American students' successful progress through the science pipeline from high school to college. Other critical factors include receiving family support and teacher encouragement, developing intrinsic motivation, and maintaining perseverance. Likewise, the presence of family support and guidance from faculty mentors are associated with the development of greater academic self-efficacy and success in the sciences for Latino students (Anaya & Cole, 2001; Cole & Espinoza, 2008; Torres & Solberg, 2001).
Beyond individual factors, campus environments play an important role in improving undergraduate success in STEM fields. At the programmatic level, offering undergraduates research opportunities can make a difference not only in attracting and retaining STEM majors, but also in facilitating students' learning in the classroom by introducing them to the benefits of what science research careers might entail (Kinkead, 2003; Lopatto, 2003). URM students who participate in well-structured undergraduate research programs receive added benefits as well, including enhancing their knowledge and comprehension of science (Sabatini, 1997); clarifying graduate school or career plans in the sciences (Hurtado, Cabrera, Lin, Arellano, & Espinosa, 2009; Kardash, 2000; Sabatini, 1997); and obtaining other professional opportunities that develop their scientific self-efficacy (Gándara & Maxwell-Jolly, 1999; Hurtado et al., 2009; Mabrouk & Peters, 2000). According to Carlone and Johnson (2007), URM students who feel, think, behave, and are recognized by meaningful others (e.g., faculty role models) as “science people” are more confident about their academic abilities. Students of color who are more likely to consider science as an important aspect of their self-identity, are also more likely to persist in their STEM major (Chang et al., 2011; Espinosa, 2011).
Several recent studies further illuminate the individual experiences and institutional attributes that can significantly improve URM students' chances of completing an undergraduate degree in a STEM field. In one longitudinal study of biomedical and behavioral science aspirants, Hurtado et al. (2007) examined the impact of college on two key outcomesin the first year of college, sense of belonging and academic adjustment. They found that the relevance of coursework to students' lives had a positive impact on academic and social adjustment for White and Asian students as well as for URMs in the sciences. Although this finding underscores the importance of experiential learning and understanding the application of knowledge for all aspiring scientists, it may also confirm previous studies, which found that URM students often leave the sciences due to a perceived lack of relevance with their social values and desire to improve conditions for their communities (Bonous-Hammarth, 2000). Moreover, campus climate may be at play as well. Hurtado et al. found that perceptions of hostile racial climates were negatively associated with the sense of belonging of all students, whereas such climates hindered the academic adjustment of only URMs. Further, Hurtado et al. found that aspiring scientists of all racial groups were more affected by financial concerns than their non-science counterparts, but URM science students were most strongly affected by such concerns, which further inhibited both their academic and social adjustment. Other national research studies have also identified effects of the campus racial climate on retention in college (Museus, Nichols, & Lambert, 2008; Titus, 2006).
Similarly, in examining key factors that influence career aspirations in science research for students entering their first year of college, Oseguera, Hurtado, Denson, Cerna, and Sáenz (2006) found that entering URM undergraduates reported working more hours during high school and were more likely to expect to work full-time during college than their White and Asian counterparts. These authors argued that having financial concerns and misperceptions about the financial viability of research professions can deter students from choosing a career in STEM fields. In contrast, they also found that participating in research-oriented programs prior to college substantially increased entering URM freshmen's interests in pursuing a scientific research career. Reinforcing these findings, Adedokun, Bessenbacher, Parker, Kirkham, and Burgess (2013) found that research skills and research self-efficacy predict student aspirations for research careers.
Unfortunately, opportunities for participating in research seem to be harder to come by for URM students when in college. In another study drawing from a similar longitudinal data set, Hurtado et al. (2008) found that African American students have significantly lower odds of participating in health science research during college compared to their White counterparts. However, African American students that attended institutions offering formal health science research opportunities to first-year students were much four times more likely to participate in research than students at institutions without such programs. Similar to findings from other studies reported earlier, Hurtado et al. (2008) found that students' concerns about financing college had a significant influence on research participation. African American students who indicated having more serious financial concerns about paying for college were significantly less likely to participate in health science research than their peers who were less concerned about finances.
Another set of studies examined factors that contributed to persisting in a STEM major through a student's first-year of undergraduate study. Chang et al. (2008) found that aspiring to attain a graduate degree increased URM students' likelihood of staying in a biomedical science major through the first-year of college by over 30%. More impressively, joining a pre-professional or departmental club during a student's freshman year increased the likelihood of persisting by more than 150%. This study also found that a URM student had a 30% higher chance of departing from a science major if he or she attended an institution where the average undergraduate combined math and verbal SAT score (the “selectivity” of the institution) was 1,100, versus one with an average of 1,000. In addition, they also found that a 100-point average undergraduate SAT score increase at the institution-level lowered the chances of biomedical persistence by 20% for all students. Similarly, Espinosa (2011) found that after 4 years of college, for every 100 point increase in institutional selectivity, women of color in STEM were almost half as likely as White women to persist in a STEM major (7.6% compared with 14.0%). So, higher institutional selectivity (measured by student achievement scores) negatively affects all science students, but the effect is stronger for URM students. Curiously, this effect does not appear to apply to those students who attended historically Black colleges or universities (HBCUs) in the first year of college; for these students the opposite tended to occur. That is, as the average undergraduate combined SAT score increased, the chances of persisting in STEM for students attending HBCUs also tended to improve (Chang et al., 2008). These studies indicate the moderating effects of selective contexts associated with race and STEM persistence in the first year of college, and with gender in the fourth year of college. The current study extends this work by examining contextual selectivity effects for all STEM aspirants, especially URM students, to the fourth year of college.
One shortcoming concerning some of the studies reviewed here is that they employed single-level statistical techniques that did not account for the multi-level nature of the data (e.g., Cole & Espinoza, 2008; Elliott et al., 1996; Grandy, 1998). Data on the college student experience is by nature multi-level, as students are “nested” within institutions. Analytical techniques that do not account for this nesting are not only less robust but also risk drawing erroneous conclusions due to misestimated standard errors. The present study further adds to the existing literature on undergraduate STEM persistence by utilizing a more robust analytical technique that can account for the multi-level nature of student data. By accounting for the institutional characteristics and student level characteristics separately, this study can more accurately assess the important contextual factors contributing to STEM degree persistence.
Taken together, the findings reported above are nicely captured in Nora et al.'s (2005) model of student persistence and degree attainment. The Nora et al. model is a reformulation of the Tinto model (1993) that brings more clarity to the academic dimensions of the college environment while maintaining social and academic integration as a central tenet. Based on research on underrepresented groups of students, Nora et al.'s integration model includes many of the factors that are likely to influence minority, low-income, and non-traditional student populations in important ways—such as aspects of pre-college socialization environments (school and home environment), financial assistance/need, family support, environmental pull factors (family and work responsibilities), and commuting to college. In reference to the academic and social experiences in college, the model emphasizes such experiences as formal and informal academic interactions with faculty, campus climates (perceptions), validating experiences (from faculty and peers), and mentoring relationships (faculty, peer, and advising staff). The model also emphasizes academic performance, academic/intellectual development, and non-cognitive gains (in psychosocial domains) as intermediate outcomes, which in turn determine persistence in college. In the current study, we incorporated measures from many of these key areas to help explain persistence in STEM at the college students entered as first-time freshman.
Hurtado (2007) suggests that sociological models of college impact should include four measurable domains of institutional and normative constructs: characterizations of the environment focusing on student perceptions of their experiences within the social and academic systems of the collegiate environment; social interactions that capture both the frequency and quality of informal academic and social engagement in college; formal memberships based on both individual interest and how the group determines entry and confers privileges on its members; and perceived social cohesion or the students' own psychological sense of integration in the college community. In multi-institutional studies, it is thus important to include relevant structural characteristics that define distinctions between colleges, such as minority enrollment and selectivity, which may further account for probabilities of STEM retention in particular types of institutions.
Building on studies of STEM student persistence and transitions in the first year (Chang et al., 2008, 2011; Hurtado et al., 2007), we adopted key constructs based on the Nora et al. (2005) integration model to detail the link between persistence in STEM to the fourth-year of college and student experiences at multiple types of 4-year colleges. Specifically, we tested the hypothesis that STEM persistence is not only a function of the characteristics students bring at college entry, but is also affected by participation in formal structures that distinguish undergraduate experiences, the racial dynamics of a college, the continuing influence of family, financial concerns, and student assessments of their own development and competence in their identity as a scientist. We apply this understanding to examine the extent to which racial disparities in science achievement can be explained by those and other factors that can then be applied to improve URM STEM degree persistence.