A comparison of integrated testlet and constructed-response question formats

Constructed-response (CR) questions are a mainstay of introductory physics textbooks and exams. However, because of time, cost, and scoring reliability constraints associated with this format, CR questions are being increasingly replaced by multiple-choice (MC) questions in formal exams. The integrated testlet (IT) is a recently-developed question structure designed to provide a proxy of the pedagogical advantages of CR questions while procedurally functioning as set of MC questions. ITs utilize an answer-until-correct response format that provides immediate confirmatory or corrective feedback, and they thus allow not only for the granting of partial credit in cases of initially incorrect reasoning, but furthermore the ability to build cumulative question structures. Here, we report on a study that directly compares the functionality of ITs and CR questions in introductory physics exams. To do this, CR questions were converted to concept-equivalent ITs, and both sets of questions were deployed in midterm and final exams. We find that both question types provide adequate discrimination between stronger and weaker students, with CR questions discriminating slightly better than the ITs. Meanwhile, an analysis of inter-rater scoring of the CR questions raises serious concerns about the reliability of the granting of partial credit when this traditional assessment technique is used in a realistic (but non optimized) setting. Furthermore, we show evidence that partial credit is granted in a valid manner in the ITs. Thus, together with consideration of the vastly reduced costs of administering IT-based examinations compared to CR-based examinations, our findings indicate that ITs are viable replacements for CR questions in formal examinations where it is desirable to both assess concept integration and to reward partial knowledge, while efficiently scoring examinations.Comment: 14 pages, 3 figures, with appendix. Accepted for publication in PRST-PER (August 2014

Hyperfine resolved spectrum of the molecular dication DCl

We have obtained hyperfine-resolved infrared spectra of a PQ23(N) branch line in the v = 2-1 band of the X 3Σ- state of the molecular dication D35Cl2+. Analysis of the hyperfine structure allows us to estimate the magnitude of the Fermi contact interaction for the chlorine nucleus; bF(Cl) = 167 (25) MHz

The Integrated Testlet: A powerful multiple-choice approach for STEM assessment.

Multiple-choice testing is becoming more common as student populations rise and instructional resources dwindle. Such testing is easy to implement, reliable, and inexpensive, yet its validity is often in question (Scott, Stelzer, & Gladding, 2006). In an effort to find inexpensive, streamlined, and valid ways to test knowledge integration and deeper levels of understanding we have introduced integrated testlets which complement recent extensions of the traditional multiple-choice approach (e.g. Ding, Reay, Lee, & Bao, 2011; and Wilcox & Pollock, 2014). Integrated testlets efficiently assess higher echelons of learning by utilizing answer-until-correct assessment tools within a set of multiple choice questions that share a common scenario and which build upon one another. These also allow for straightforward and demonstrably-valid granting of partial credit. Integrated testlets enable conceptual scaffolding to be tested and, if desired, assembled during the assessment. Thus, they serve both summative and formative purposes. In this workshop we will introduce examples of integrated testlets that span the STEM disciplines. Participants will actively engage with one or two testlets of their choosing to gain experience with both the technology and the workings of this assessment tool. Time will then be devoted to unpacking these experiences and to highlighting the pedagogical implications of being able to assess integration of knowledge within a multiple-choice framework. Finally we will discuss how integrated testlets are currently transforming students’ learning experiences at Trent University. Wilcox, B.R., & Pollock, S. J. (2014). Coupled multiple-response versus free-response conceptual assessment: An example from upper-division physics. Physical Review Special Topics - Physics Education Research, 10(2), 020124-1 – 020124-11. http://dx.doi.org/10.1103/physrevstper.10.020124 Ding, L., Reay, N., Lee, A., & Bao, L. (2009). Exploring the role of conceptual scaffolding in solving synthesis problems. Physical Review Special Topics - Physics Education Research, 7(2), 020109-1 – 020109-11. http://dx.doi.org/10.1103/physrevstper.7.020109 Scott, M., Stelzer, T., & Gladding, G. (2009). Evaluating multiple-choice exams in large introductory physics courses. Physical Review Special Topics - Physics Education Research, 2(2), 020102-1 – 020102-14. http://dx.doi.org/10.1103/physrevstper.7.02010

Observation of molecular hyperfine structure in the extreme ultraviolet: The HF C-X spectrum

Clearly resolved hyperfine structure has been observed in the extreme ultraviolet (XUV) spectra of the C Π1, v=0-X 1 +, v=0 transition of H F 19 obtained through 1 XUV+1 UV resonance enhanced multiphoton ionization spectroscopy. The hyperfine splitting within the R -branch lines shows significant perturbations, which we attribute to mixing with the rotational levels of the nearby v=29 level of the B 1 + ion-pair state. A deperturbation analysis quantitatively explains the apparent variation of the fluorine magnetic hyperfine parameter aF, for which a value of 4034(83) MHz was obtained by averaging over the values derived from the R (0) -R (4) lines, after correcting for the effects of the perturbations. © 2008 American Institute of Physics