CONSTRUCT VALIDATION OF A MEASURE TO ASSESS SUSTAINABILITY OF SCHOOL‐WIDE BEHAVIOR INTERVENTIONS

This study assessed aspects of construct validity of the School‐wide Universal Behavior Sustainability Index–School Teams (SUBSIST), a measure evaluating critical features of the school context related to sustainability of school‐wide interventions. Participants at 217 schools implementing School‐wide Positive Behavior Support (SWPBS) were administered the measure. A two‐step cluster analysis was performed to classify schools based on responses to the 39 SUBSIST items. A two‐cluster solution was obtained, with schools in one cluster (n = 139) obtaining significantly higher scores on SUBSIST items than schools in the other cluster (n = 78). The most critical item that contributed to cluster formation was the use of data for decision making. Results also showed that higher sustainability scores were associated with increased frequency of school team meetings, presentation of data to school staff, access to an external coach/consultant, and greater number of years implementing SWPBS. These results are discussed with regard to implications for sustaining school‐wide interventions.     

Binary Interpolative Coding for Effective Index Compression

Information retrieval systems contain large volumes of text, and currently have typical sizes into the gigabyte range. Inverted indexes are one important method for providing search facilities into these collections, but unless compressed require a great deal of space. In this paper we introduce a new method for compressing inverted indexes that yields excellent compression, fast decoding, and exploits clustering—the tendency for words to appear relatively frequently in some parts of the collection and infrequently in others. We also describe two other quite separate applications for the same compression method: representing the MTF list positions generated by the Burrows-Wheeler Block Sorting transformation; and transmitting the codebook for semi-static block-based minimum-redundancy coding.     

Solving the mystery of vanishing rivers in China

A major controversy was sparked worldwide by a recent national water census claiming that the number of Chinese rivers with watersheds ≥100 km² was less than half the previous estimate of 50 000 rivers, which also stimulates debates on the potential causes and consequences. Here, we estimated the number of rivers in terms of stream-segmentation characteristics described by Horton, Strahler and Shreve stream-order rules, as well as their mixed mode for named rivers recorded in the Encyclopedia of Rivers and Lakes in China. As a result, the number of ‘vanishing rivers’ has been found to be highly relevant to statistical specifications in addition to the erroneous inclusion of pseudo-rivers primarily generated in arid or frost-thaw areas. The modified Horton stream-order scheme reasonably depicts the configuration of complete natural streams from headwater to destination, while the Strahler largely projects the fragmentation of the named river networks associated with human aggregation to the hierarchical river systems.     

Click-based evidence for decaying weight distributions in search effectiveness metrics

Search effectiveness metrics are used to evaluate the quality of the answer lists returned by search services, usually based on a set of relevance judgments. One plausible way of calculating an effectiveness score for a system run is to compute the inner-product of the run’s relevance vector and a “utility” vector, where the ith element in the utility vector represents the relative benefit obtained by the user of the system if they encounter a relevant document at depth i in the ranking. This paper uses such a framework to examine the user behavior patterns—and hence utility weightings—that can be inferred from a web query log. We describe a process for extrapolating user observations from query log clickthroughs, and employ this user model to measure the quality of effectiveness weighting distributions. Our results show that for measures with static distributions (that is, utility weighting schemes for which the weight vector is independent of the relevance vector), the geometric weighting model employed in the rank-biased precision effectiveness metric offers the closest fit to the user observation model. In addition, using past TREC data as to indicate likelihood of relevance, we also show that the distributions employed in the BPref and MRR metrics are the best fit out of the measures for which static distributions do not exist.     

Pedagogical Signals of Faculty Approachability: Factors Shaping Faculty–Student Interaction Outside the Classroom

Decades of research demonstrate that college students benefit from positive interaction with faculty members, although that same evidence suggests that those interactions are far from common, particularly outside the classroom. Moreover, relatively little is known about which, when, how, and why faculty members choose to engage with students outside of the classroom. Guided by the theory that faculty members use in-class behaviors to signal their “psychosocial approachability” for out-of-class interaction with students (Wilson et al. in Sociology of Education 47(1):74–92, 1974; College professors and their impact on students, 1975), this study uses data from 2,845 faculty members on 45 campuses to identify the personal, institutional, and pedagogical factors that influence the frequency and type of interaction faculty members have with students outside of the classroom.     

Looking back,looking forward: celebrating a quarter century of serving distance education ‘down under’

The Open and Distance Learning Association of Australia (ODLAA) has reached 25 years of age. This article traces the development of the Association over that period. It records the major changes that have taken place in the range and types of activities of the Association and explains the circumstances that led to those changes. It concludes by attempting to identify the principal challenges facing the Association in entering its second quarter century and proposes ways in which these challenges might be addressed.