A Comparison of Item Calibration Procedures in the Presence of Test Speededness     

Youngsuk Suh  Sun‐Joo Cho  James A. Wollack 《Journal of Educational Measurement》2012,49(3):285-311

In the presence of test speededness, the parameter estimates of item response theory models can be poorly estimated due to conditional dependencies among items, particularly for end‐of‐test items (i.e., speeded items). This article conducted a systematic comparison of five‐item calibration procedures—a two‐parameter logistic (2PL) model, a one‐dimensional mixture model, a two‐step strategy (a combination of the one‐dimensional mixture and the 2PL), a two‐dimensional mixture model, and a hybrid model‐–by examining how sample size, percentage of speeded examinees, percentage of missing responses, and way of scoring missing responses (incorrect vs. omitted) affect the item parameter estimation in speeded tests. For nonspeeded items, all five procedures showed similar results in recovering item parameters. For speeded items, the one‐dimensional mixture model, the two‐step strategy, and the two‐dimensional mixture model provided largely similar results and performed better than the 2PL model and the hybrid model in calibrating slope parameters. However, those three procedures performed similarly to the hybrid model in estimating intercept parameters. As expected, the 2PL model did not appear to be as accurate as the other models in recovering item parameters, especially when there were large numbers of examinees showing speededness and a high percentage of missing responses with incorrect scoring. Real data analysis further described the similarities and differences between the five procedures.  相似文献   

Does a Knowledge Generation Approach to Learning Benefit Students? A Systematic Review of Research on the Science Writing Heuristic Approach     

Hand  Brian  Chen  Ying-Chih  Suh  Jee Kyung 《Educational Psychology Review》2021,33(2):535-577

Educational Psychology Review - The shifting emphases of new national curricula have placed more attention on knowledge generation approaches to learning. Such approaches are centered on the...  相似文献   

Processes of Early Childhood Interventions to Adult Well‐Being          下载免费PDF全文

Arthur J. Reynolds  Suh‐Ruu Ou  Christina F. Mondi  Momoko Hayakawa 《Child development》2017,88(2):378-387

This article describes the contributions of cognitive–scholastic advantage, family support behavior, and school quality and support as processes through which early childhood interventions promote well‐being. Evidence in support of these processes is from longitudinal cohort studies of the Child–Parent Centers and other preventive interventions beginning by age 4. Relatively large effects of participation have been documented for school readiness skills at age 5, parent involvement, K‐12 achievement, remedial education, educational attainment, and crime prevention. The three processes account for up to half of the program impacts on well‐being. They also help to explain the positive economic returns of many effective programs. The generalizability of these processes is supported by a sizable knowledge base, including a scale up of the Child–Parent Centers.  相似文献   

A large-area hemispherical perforated bead microarray for monitoring bead based aptamer and target protein interaction     

Jong Seob Choi  Sunwoong Bae  Kyung Hoon Kim  Tae Seok Seo 《Biomicrofluidics》2014,8(6)

Herein, we present a large-area 3D hemispherical perforated microwell structure for a bead based bioassay. Such a unique microstructure enables us to perform the rapid and stable localization of the beads at the single bead level and the facile manipulation of the bead capture and retrieval with high speed and efficiency. The fabrication process mainly consisted of three steps: the convex micropatterned nickel (Ni) mold production from the concave micropatterned silicon (Si) wafer, hot embossing on the polymer matrix to generate the concave micropattened acrylate sheet, and reactive ion etching to make the bottom holes. The large-area hemispherical perforated micropatterned acrylate sheet was sandwiched between two polydimethylsiloxane (PDMS) microchannel layers. The bead solution was injected and recovered in the top PDMS microchannel, while the bottom PDMS microchannel was connected with control lines to exert the hydrodynamic force in order to alter the flow direction of the bead solution for the bead capture and release operation. The streptavidin-coated microbead capture was achieved with almost 100% yield within 1 min, and all the beads were retrieved in 10 s. Lysozyme or thrombin binding aptamer labelled microbeads were trapped on the proposed bead microarray, and the in situ fluorescence signal of the bead array was monitored after aptamer-target protein interaction. The protein-aptamer conjugated microbeads were recovered, and the aptamer was isolated for matrix assisted laser desorption/ionization time-of-flight mass spectrometry analysis to confirm the identity of the aptamer.  相似文献   

An economic valuation study of public libraries in Korea     

Young Man Ko  Wonsik Shim  Soon-Hee Pyo  Ji Sang Chang  Hye Kyung Chung 《Library & information science research》2012

The economic value of public libraries for local residents in Korea was measured. An economic-value measurement model that enables the estimation of diverse types of public library services was designed, using a conditional-value measurement method. Benefits were taken as the value of the main services provided by public libraries, such as accessibility to informational materials, facilities, and programs. Costs included the total amount of expenses at libraries such as personnel expenses, materials purchasing expenses, and other operational costs. Data were collected from 1220 users from 22 public libraries in the province of Seoul/Gyeonggi-do and the other seven Korean provinces. The return on investment (ROI) was calculated to be 3.66.  相似文献