A day in the life of PubMed: analysis of a typical day's query log.

OBJECTIVE: To characterize PubMed usage over a typical day and compare it to previous studies of user behavior on Web search engines. DESIGN: We performed a lexical and semantic analysis of 2,689,166 queries issued on PubMed over 24 consecutive hours on a typical day. MEASUREMENTS: We measured the number of queries, number of distinct users, queries per user, terms per query, common terms, Boolean operator use, common phrases, result set size, MeSH categories, used semantic measurements to group queries into sessions, and studied the addition and removal of terms from consecutive queries to gauge search strategies. RESULTS: The size of the result sets from a sample of queries showed a bimodal distribution, with peaks at approximately 3 and 100 results, suggesting that a large group of queries was tightly focused and another was broad. Like Web search engine sessions, most PubMed sessions consisted of a single query. However, PubMed queries contained more terms. CONCLUSION: PubMed's usage profile should be considered when educating users, building user interfaces, and developing future biomedical information retrieval systems.

An Extended Hierarchical Task Analysis for Error Prediction in Medical Devices

This paper introduces an extended hierarchical task analysis (HTA) methodology devised to evaluate and compare user interfaces on volumetric infusion pumps. The pumps were studied along the dimensions of overall usability and propensity for generating human error. With HTA as our framework, we analyzed six pumps on a variety of common tasks using Norman’s Action theory. The introduced method of evaluation divides the problem space between the external world of the device interface and the user’s internal cognitive world, allowing for predictions of potential user errors at the human-device level. In this paper, one detailed analysis is provided as an example, comparing two different pumps on two separate tasks. The results demonstrate the inherent variation, often the cause of usage errors, found with infusion pumps being used in hospitals today. The reported methodology is a useful tool for evaluating human performance and predicting potential user errors with infusion pumps and other simple medical devices.

Assessing fun in serious games: Formative evaluation of games from two diabetes prevention interventions

Purpose. To determine the usability of two video games to prevent type 2 diabetes and obesity among youth through analysis of data collected during alpha-testing. ^ Subjects. Ten children aged 9 to 12 were selected for three 2-hour alpha testing sessions.^ Methods. "Escape from Diab" and "Nanoswarm" were designed to change dietary and physical inactivity behaviors, based on a theoretical framework of mediating variables obtained from social cognitive theory, self-determination theory, elaboration likelihood model, and behavioral inoculation theory. Thirteen mini-games developed by the software company were divided into 3 groups based on completion date. Children tested 4-5 mini-games in each of three sessions. Observed game play was followed by a scripted interview. Results from observation forms and interview transcripts were tabulated and coded to determine usability. Suggestions for game modifications were delivered to the software design firm, and a follow-up table reports rationale for inclusion or exclusion of such modifications.^ Results. Participants were 50% frequent video game players and 20% non game-players. Most (60%) were female. The mean grade (indicating likeability as a subset of usability) across all games given by children was significantly greater than a neutral grade of 80% (89%, p < 0.01), indicating a positive likeability score. The games on average also received positive ratings for fun, helpfulness of instructions and length compared to neutral values (midpoint on likert scales) (all p < 0.01). Observation notes indicated that participants paid attention to the instructions, did not appear to have much difficulty with the games, and were "not frustrated", "not bored", "very engaged", "not fidgety" and "very calm" (all p < 0.01). The primary issues noted in observations and interviews were unclear instructions and unclear purpose of some games. Player suggestions primarily involved ways to make on screen cues more visible or noticeable, instructions more clear, and games more elaborate or difficult.^ Conclusions. The present study highlights the importance of alpha testing video game components for usability prior to completion to enhance usability and likeability. Results indicate that creating clear instructions, making peripheral screen cues more eye-catching or noticeable, and vigorously stating the purpose of the game to improve understandability are important elements. However, future interventions will each present unique materials and user-interfaces and should therefore also be thoroughly alpha-tested. ^