Developed by Kathryn Williamson and Shannon Willoboughby
|Purpose||To assess introductory general education college astronomy (“Astro 101”) students' understanding of Newtonian gravity.|
|Focus||Astronomy Content knowledge (directionality of gravity, force law, thresholds related to gravity, independence of forces)|
Sample questions from the NGCI:
This is the second highest level of research validation, corresponding to at least 5 of the validation categories below.
Research Validation Summary
Based on Research Into:
- Student thinking
- Student interviews
- Expert review
- Appropriate statistical analysis
- At multiple institutions
- By multiple research groups
- Peer-reviewed publication
The multiple-choice questions on the NGCI were developed based on previous research on student ideas about gravity. The authors started with concept map with four aspects of gravity (concept domains), which were used to create the initial set of test questions. The questions underwent several rounds of testing and revision, which consisted of giving the questions to students and analyzing the responses, student interviews and expert review. Appropriate statistical analysis of reliability, difficulty and discrimination were conducted and reasonable values found. A wide range of normalized gain scores were found for different courses, indicating that that NGCI is sensitive to differences in instruction. The NGCI has been used with over 900 students at six institutions and results are published in one peer-reviewed publication.
- K. Williamson and S. Willoughby, Student Understanding of Gravity in Introductory College Astronomy, Astron. Educ. Rev. 11 (1), 1 (2012).
- K. Williamson, S. Willoughby, and E. Prather, Development of the Newtonian Gravity Concept Inventory, Astron. Educ. Rev. 12 (1), 1 (2013).
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Typical scores on the NGCI as given in Table 2 of Williamson and Willoughby 2013:
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The latest version of the NGCI, released in 2013, is version 3.