Award Date

May 2018

Degree Type


Degree Name

Doctor of Philosophy (PhD)


Chemistry and Biochemistry

First Committee Member

MaryKay Orgill

Second Committee Member

Kathleen Robins

Third Committee Member

Clemens Heske

Fourth Committee Member

Christine Clark

Number of Pages



Because language provides the framework through which knowledge is constructed, it is crucial to consider the ways in which students with limited English proficiencies are able to express their understanding. English language learners (ELLs) make up a significant portion of the student body in the education system and represent many ethnic and racial minorities in STEM (Science, Technology, Engineering & Mathematics) fields (Burke & Mattis, 2007). Despite the national push to build a more diversified, STEM-ready workforce, there is little research that considers the way ELLs are assessed in STEM courses at the postsecondary level. Literature reports that science tests that assess the knowledge of students who are still in the process of learning language skills are inadequate and threaten the validity of assessments. The way students interpret and respond to test items are mediated by linguistic and cultural factors, such as home language and prior educational experiences in the country of origin. Therefore, language and cultural factors must be taken into consideration in order to improve the validity of classroom assessments in science courses.

Students’ experiences in introductory science courses, such as biology and general chemistry, are critical in their choice of staying in or switching out of STEM majors (Astin & Astin, 1992). Of these, general chemistry is one of the most feared science courses for undergraduate students (Carter & Brickhouse, 1989), and it is a required course for many STEM-bound career paths. Most students struggle with understanding chemistry and many do not succeed on chemistry assessments (Woldeamanuel et al., 2014). Research suggests that scientific language literacy has a significant influence on all students’ success in chemistry assessments, including that of both ELLs and Native English Speakers (NES) (Woldeamanuel et al., 2014). Therefore, one way to support the success of all students—and particularly of ELLs—on chemistry assessments is to address the linguistic complexity inherent in chemistry assessment questions.

One way to ease the burden of linguistic complexity during testing is to apply the Equity Framework of Classroom Assessments (EFCA) (Siegel, 2008) to written test items. This framework aims to make test items more accessible without simplifying the content. In general chemistry, the EFCA can be implemented to make commonly-used items more accessible to all students using modifications such as division of prompt into smaller parts, reduction of non-essential information, adding representation, and simplifying sentence structure.

This study investigated the perceptions of ELL and NES students about general chemistry assessment items that were modified according to the EFCA. ELL students reported to experience difficulties understanding items that included complex linguistic features such as complex sentence structures and vocabulary. The results show that ELLs perceived language-independent features of items to be the most helpful on assessment items. These features included the formatting of items and the visual representations embedded in items. Although NES students also found the visual features of items to be helpful, they used language-dependent features to understand and set up the problems.

The results suggest that ELL students particularly benefited from scaffolding-related features in assessment items. Features that provided content support and guidance for identifying key information and setting up the problems were more helpful for ELL than NES students.

Both groups of students found features that provided contextualization in the form of storylines and/or background information which were not directly related to solving the assessment items to be irrelevant, challenging, and/or confusing. Both groups of students reported that they preferred the revised versions—which included the modifications recommended by the EFCA—over the original versions of the assessment items presented to them. The findings suggest that most of the modifications employed in the EFCA are effective in mitigating linguistically complex elements of written assessments items about limiting reactant and percent yield in general chemistry and support the assessment of both ELL and NES students.


Assessment; Chemistry; English language learner; Equity; Language; Undergraduate


Chemistry | Education | Educational Assessment, Evaluation, and Research

File Format


Degree Grantor

University of Nevada, Las Vegas




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