The sensitivity and precision of search terms in Phases I, II and III of the Cochrane Highly Sensitive Search Strategy for identifying reports of randomized trials in medline in a specific area of health care--HIV/AIDS prevention and treatment interventions

OBJECTIVES: To detect term(s) in the Cochrane Highly Sensitive Search Strategy (HSSS) that retain high sensitivity but improve precision in retrieving reports of trials in the PubMed version of medline. METHODS: Individual terms from the PubMed version of the HSSS were added, term by term, to an African HIV/AIDS strategy to identify reports of trials in medline using PubMed. The titles and abstracts of the records retrieved were read by two handsearchers and checked by a clinical epidemiologist. The sensitivity and precision of each term in the three phases of the HSSS were calculated. RESULTS: Of 7,719 records retrieved, 285 were identified as reports of trials [204 randomized (RCTs); 81 possibly randomized or quasi-randomized (CCTs)]. Phase III had the highest sensitivity (92%). Overall, precision was very low (3.7%). One term, 'random*[tw]', retrieved all RCTs found by our search and improved precision to 29%. The least sensitive terms, yielding no records, were '(doubl* AND mask*)[tw]' and terms containing 'trebl*' or 'tripl*', except for '(tripl* AND blind*)[tw]'. The highest precision per term was for 'Double-blind Method [MeSH]' (76%). CONCLUSIONS: To retrieve all RCTs and CCTs found by our search, seven terms are needed but precision remains low (4.3%). Developments in the methods of search strategy design may help to improve precision while retaining high levels of sensitivity by identifying term(s) which occur frequently in relevant records and are the most efficient at discriminating between different study designs.     

Developing a geographic search filter to identify randomised controlled trials in Africa: finding the optimal balance between sensitivity and precision

Background: Research on identifying trials using geographic filters is limited. Objectives:  To test the sensitivity and precision of a filter to identify African randomised controlled trials (RCTs). Methods: We searched medline and embase for RCTs published in 2004 using a Cochrane filter for RCTs. The search was limited to HIV/AIDS but irrespective of location. Two investigators independently identified African RCTs from the retrieved records forming a reference set. We then repeated the search using an African geographic filter comprising country and regional terms forming the filter set. We compared the sensitivity and precision of the sets. Results: The medline reference set comprised 1799 records with 23 African RCTs; for embase , the reference set comprised 763 records with 37 African RCTs. The medline filter set comprised 180 records with 17 African RCTs; the embase filter set comprised 98 records with 27 African RCTs. Sensitivity of the filter was 74% (medline ) and 73% (embase ). Addition of the filter improved precision from 1.3% to 9.4% (medline ) and from 5% to 28% (embase ). Conclusion: The African filter improved precision with some loss in sensitivity. Incomplete reporting of trial location in electronic bibliographic records restricts efficiency of geographic filters. Prospective trial registration should alleviate this.     

How do teachers perceive cheating students? Beliefs about cues to deception and detection accuracy in the educational field

The present study explores how well teacher trainees can detect liars. Moreover, a new method was applied to investigate beliefs that teacher trainees hold about liars. The results indicate that, overall, teacher trainees were not better than chance in detecting true and invented stories. Generally, participants reported to have used only a few cues for their credibility judgment, where most of these self-reported cues are stereotypical and invalid deception cues (e.g., gaze aversion). Further analyses with a Brunswikian lens model showed that the self-reported cues were good predictors of their credibility judgment but only poorly predictive for the objective truth/lie status of the statement. Practical implications of the results are discussed.     

Developing and validating science education videodiscs

The development of videodiscs for science instruction in public schools requires a recognition of the unique characteristics of the public school environment and a sensitivity to the persistent problems associated with science instruction. This report discusses the conceptualization, development, and formative evaluation of a series of science education videodiscs. The discs were designed to enhance the efforts of teachers working in both individual and group instructional settings. In presenting the content, particular attention was given to the “effective instruction” research literature and more subject-matter–specific problems such as those associated with the use of terminology and the fragmentation of information. The formative data indicated that videodisc programs can enhance the effectiveness of teachers and substantively impact student achievement and attitudes.     

Class size and achievement in introductory economics: Evidence from the TUCE III data

Does class size affect achievement in introductory economics? This paper addresses this question using a national economic education data base (TUCE III), consolidating these data so that each observation represents a single class rather than a single student, thereby alleviating several estimation problems that plague empirical work in this area. Our results indicate that class size does not affect student achievement, and further, that class characteristics over which instructors or department chairs have control also do not influence achievement. These results are remarkably robust to different specifications, so long as students' Scholastic Aptitude Test (SAT) scores are used to control for ability and account is taken of whether the TUCE test result counted toward the students' final grade.     

Pre-K-8 prospective teachers’ understanding of fractions: An extension of fractions schemes and operations research

In an effort to expand our knowledge base pertaining to pre-K-8 prospective teachers’ understanding of fractions, the present study was designed to extend the work on fractions schemes and operations to this population. One purpose of our study was to validate the fractions schemes and operations hierarchy with the pre-K-8 prospective teacher population to determine whether this population follows the same trajectory as upper elementary and middle school students. A second purpose of our study was to identify which of the fractions schemes and operations our sample of prospective teachers demonstrated evidence of having constructed along with what this tells us about prospective teachers’ understanding of fractions. We were able to validate the hierarchy for this population, meaning that each lower-level fraction scheme/operation appeared to be a prerequisite to the higher-level schemes/operations. We found that although most of the prospective teachers had constructed the lower-level schemes and operations, less than half had constructed the more sophisticated ones. An unexpected result related to the association between the coordination of three levels of units and the iterative fraction scheme is addressed. Prospective teachers’ reliance on procedural knowledge related to fractions also presented a challenge to assessing, in particular, their ability to coordinate three levels of units. We conclude with implications for research and practice in mathematics courses intended for pre-K-8 prospective teachers.     

Making connections in mathematics

Math textbooks, which usually represent the mathematics curriculum, seem to be linked to the poor math performance of U.S. students. The major shortcomings of math textbooks are described in this article; then an alternative perspective is offered (the sameness analysis), along with research conducted with students with learning disabilities and at-risk students. The article then presents a detailed illustration of the sameness analysis--how to teach the addition-subtraction and multiplication-division relationships and their interrelationships in the context of solving word problems in mathematics.