Reducing Conditional Error Variance Differences in IRT Scaling

2018 ◽  
pp. 147-161
Author(s):  
Tammy J. Trierweiler ◽  
Charles Lewis ◽  
Robert L. Smith
Keyword(s):  
Error Variance

Measuring the Big Five in Self-Report and Other Ratings

2000 ◽  
Vol 16 (1) ◽  
pp. 31-43 ◽  
Author(s):  
Claudio Barbaranelli ◽  
Gian Vittorio Caprara
Keyword(s):  
Big Five ◽  
Structural Equation ◽  
Structural Equation Models ◽  
Error Variance ◽  
The Self ◽  
Self Report ◽  
Sources Of Information ◽  
Third Person ◽  
Fit Indexes ◽  
Response Modes

Summary: The aim of the study is to assess the construct validity of two different measures of the Big Five, matching two “response modes” (phrase-questionnaire and list of adjectives) and two sources of information or raters (self-report and other ratings). Two-hundred subjects, equally divided in males and females, were administered the self-report versions of the Big Five Questionnaire (BFQ) and the Big Five Observer (BFO), a list of bipolar pairs of adjectives ( Caprara, Barbaranelli, & Borgogni, 1993 , 1994 ). Every subject was rated by six acquaintances, then aggregated by means of the same instruments used for the self-report, but worded in a third-person format. The multitrait-multimethod matrix derived from these measures was then analyzed via Structural Equation Models according to the criteria proposed by Widaman (1985) , Marsh (1989) , and Bagozzi (1994) . In particular, four different models were compared. While the global fit indexes of the models were only moderate, convergent and discriminant validities were clearly supported, and method and error variance were moderate or low.

Revision of a Criterion-Referenced Vocabulary Test Using Generalizability Theory

2009 ◽  
Vol 31 (1) ◽  
pp. 81
Author(s):  
Takeaki Kumazawa
Keyword(s):  
Generalizability Theory ◽  
Classical Test Theory ◽  
Performance Testing ◽  
Error Variance ◽  
Test Theory ◽  
Vocabulary Test ◽  
Multiple Sources ◽  
Generalizability Coefficient ◽  
Criterion Referenced ◽  
Generalizability Study

Classical test theory (CTT) has been widely used to estimate the reliability of measurements. Generalizability theory (G theory), an extension of CTT, is a powerful statistical procedure, particularly useful for performance testing, because it enables estimating the percentages of persons variance and multiple sources of error variance. This study focuses on a generalizability study (G study) conducted to investigate such variance components for a paper-pencil multiple-choice vocabulary test used as a diagnostic pretest. Further, a decision study (D study) was conducted to compute the generalizability coefficient (G coefficient) for absolute decisions. The results of the G and D studies indicated that 46% of the total variance was due to the items effect; further, the G coefficient for absolute decisions was low. 古典的テスト理論は尺度の信頼性を測定するため広く用いられている。古典的テスト理論の応用である一般化可能性理論（G理論）は特にパフォーマンステストにおいて有効な分析手法であり、受験者と誤差の要因となる分散成分の割合を測定することができる。本研究では診断テストとして用いられた多岐選択式語彙テストの分散成分を測定するため一般化可能性研究（G研究）を行った。さらに、決定研究（D研究）では絶対評価に用いる一般化可能性係数を算出した。G研究とD研究の結果、項目の分散成分が全体の分散の46%を占め、また信頼度指数は高くなかった。

Effects of Accounting-Method Choices on Subjective Performance-Measure Weighting Decisions: Experimental Evidence on Precision and Error Covariance

2005 ◽  
Vol 80 (4) ◽  
pp. 1163-1192 ◽  
Author(s):  
Ranjani Krishnan ◽  
Joan L. Luft ◽  
Michael D. Shields
Keyword(s):  
Performance Measures ◽  
Error Variance ◽  
Spillover Effects ◽  
Performance Measure ◽  
Incentive System ◽  
Experimental Setting ◽  
Error Covariance ◽  
Psychology Theory ◽  
Optimal Weighting ◽  
Similarity And Difference

Performance-measure weights for incentive compensation are often determined subjectively. Determining these weights is a cognitively difficult task, and archival research shows that observed performance-measure weights are only partially consistent with the predictions of agency theory. Ittner et al. (2003) have concluded that psychology theory can help to explain such inconsistencies. In an experimental setting based on Feltham and Xie (1994), we use psychology theories of reasoning to predict distinctive patterns of similarity and difference between optimal and actual subjective performance-measure weights. The following predictions are supported. First, in contrast to a number of prior studies, most individuals' decisions are significantly influenced by the performance measures' error variance (precision) and error covariance. Second, directional errors in the use of these measurement attributes are relatively frequent, resulting in a mean underreaction to an accounting change that alters performance measurement error. Third, individuals seem insufficiently aware that a change in the accounting for one measure has spillover effects on the optimal weighting of the other measure in a two-measure incentive system. In consequence, they make performance-measure weighting decisions that are likely to result in misallocations of agent effort.

scholarly journals Global 3D Features of Error Variances of GPS Radio Occultation and Radiosonde Observations

2020 ◽  
Vol 13 (1) ◽  
pp. 1
Author(s):  
Xu Xu ◽  
Xiaolei Zou
Keyword(s):  
Radio Occultation ◽  
Weather Prediction ◽  
Lower Troposphere ◽  
Error Variance ◽  
Specific Humidity ◽  
Temperature Error ◽  
Observation Error ◽  
Bending Angle ◽  
Gps Radio Occultation ◽  
Low Latitudes

Global Positioning System (GPS) radio occultation (RO) and radiosonde (RS) observations are two major types of observations assimilated in numerical weather prediction (NWP) systems. Observation error variances are required input that determines the weightings given to observations in data assimilation. This study estimates the error variances of global GPS RO refractivity and bending angle and RS temperature and humidity observations at 521 selected RS stations using the three-cornered hat method with additional ERA-Interim reanalysis and Global Forecast System forecast data available from 1 January 2016 to 31 August 2019. The global distributions, of both RO and RS observation error variances, are analyzed in terms of vertical and latitudinal variations. Error variances of RO refractivity and bending angle and RS specific humidity in the lower troposphere, such as at 850 hPa (3.5 km impact height for the bending angle), all increase with decreasing latitude. The error variances of RO refractivity and bending angle and RS specific humidity can reach about 30 N-unit2, 3 × 10−6 rad2, and 2 (g kg−1)2, respectively. There is also a good symmetry of the error variances of both RO refractivity and bending angle with respect to the equator between the Northern and Southern Hemispheres at all vertical levels. In this study, we provide the mean error variances of refractivity and bending angle in every 5°-latitude band between the equator and 60°N, as well as every interval of 10 hPa pressure or 0.2 km impact height. The RS temperature error variance distribution differs from those of refractivity, bending angle, and humidity, which, at low latitudes, are smaller (less than 1 K2) than those in the midlatitudes (more than 3 K2). In the midlatitudes, the RS temperature error variances in North America are larger than those in East Asia and Europe, which may arise from different radiosonde types among the above three regions.

scholarly journals Asymptotic Prediction Error Variance for Feedforward Neural Networks

2020 ◽  
Vol 53 (2) ◽  
pp. 1108-1113
Author(s):  
Magnus Malmström ◽  
Isaac Skog ◽  
Daniel Axehill ◽  
Fredrik Gustafsson
Keyword(s):  
Neural Networks ◽  
Prediction Error ◽  
Feedforward Neural Networks ◽  
Error Variance ◽  
Prediction Error Variance

scholarly journals The association between body mass index and recovery from post-traumatic stress disorder after the nuclear accident in Fukushima

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Masato Nagai ◽  
Tetsuya Ohira ◽  
Masaharu Maeda ◽  
Seiji Yasumura ◽  
Itaru Miura ◽  
...  
Keyword(s):  
Body Mass Index ◽  
Body Mass ◽  
Post Traumatic Stress Disorder ◽  
Traumatic Stress ◽  
Stress Disorder ◽  
Error Variance ◽  
Normal Weight ◽  
Post Traumatic Stress ◽  
Post Traumatic

AbstractPost-traumatic stress disorder (PTSD) and obesity share common risk factors; however, the effect of obesity on recovery from PTSD has not been assessed. We examined the association between body mass index (BMI) and recovery from PTSD after the Great East Japan Earthquake. We analyzed 4356 men and women with probable PTSD aged ≥ 16 years who were living in evacuation zones owing to the radiation accident in Fukushima, Japan. Recovery from probable PTSD was defined as Post-traumatic Stress Disorder Checklist-specific scores < 44. Using Poisson regression with robust error variance adjusted for confounders, we compared the prevalence ratios (PRs) and 95% confidence intervals (CIs) for this outcome in 2013 and 2014. Compared with point estimates for normal weight (BMI: 18.5–24.9 kg/m2), especially in 2013, those for underweight (BMI: < 18.5 kg/m2) and obesity (BMI: ≥ 30.0 kg/m2) tended to slightly increase and decrease, respectively, for recovery from probable PTSD. The multivariate-adjusted PRs (95% CIs) for underweight and obesity were 1.08 (0.88–1.33) and 0.85 (0.68–1.06), respectively, in 2013 and 1.02 (0.82–1.26) and 0.87 (0.69–1.09), respectively, in 2014. The results of the present study showed that obesity may be a useful predictor for probable PTSD recovery. Obese victims with PTSD would require more intensive support and careful follow-up for recovery.

scholarly journals 964. Impact of Doxycycline as Malaria Prophylaxis on Risk of Influenza Like Illness Among International Travelers

2018 ◽  
Vol 5 (suppl_1) ◽  
pp. S35-S35
Author(s):  
Kathryn Lago ◽  
Kalyani Telu ◽  
David R Tribble ◽  
Anuradha Ganesan ◽  
Anjali Kunz ◽  
...  
Keyword(s):  
Disease Transmission ◽  
Regression Models ◽  
Prospective Observational Study ◽  
Female Gender ◽  
Error Variance ◽  
Respiratory Pathogens ◽  
Malaria Prophylaxis ◽  
Influenza Like Illness ◽  
Increased Risk ◽  
The Caribbean

Abstract Background International travelers are often at risk for both influenza like illness (ILI) and malaria. Doxycycline is active against many pathogens causing ILI and is routinely used for malaria prophylaxis. We evaluated the incidence of and risk factors for ILI, and whether the choice of malaria prophylaxis was associated with ILI. Methods TravMil is a prospective observational study enrolling subjects presenting to 6 military travel clinics. We analyzed pre- and post-travel surveys from travelers to regions outside of the continental United States, Western or Northern Europe, Canada, or New Zealand between July 2010 and August 2018. ILI was defined as subjective fever associated with either a sore throat or cough. Characteristics of trip and traveler and the use of malaria prophylaxis were analyzed to determine association with development of ILI. Poisson regression models with robust error variance were used to estimate relative risk of ILI. Results A total of 3,227 travelers were enrolled: 62.1% male, median age of 39 (IQR 27, 59), median travel duration 19 days (IQR 12, 49). 32% traveled to Africa, 40% to Asia, and 27% to the Caribbean, Mexico, and Central or South America. Military travel (46%) and vacation (40%) were most common reasons for travel. Twenty percent took doxycycline for malaria prophylaxis, 50% other prophylaxis (89% atovaquone–proguanil), and 30% took none. 8.7% developed ILI. Compared with those on no or other prophylaxis, doxycycline was associated with decreased risk of ILI [RR 0.65 (0.43–0.99), P = 0.046], as was military travel [RR 0.30 (0.21–0.43), P &lt; 0.01]. Increased risk of ILI was associated with female gender [RR 1.57 (1.24–1.98), P &lt; 0.01], travel to Asia [RR 1.37 (1.08–1.75), P = 0.01], cruises [RR 2.21 (1.73–2.83), P &lt; 0.01], and longer duration of travel [RR 1.01 (1.00–1.01, P &lt; 0.01]. Conclusion The use of doxycycline is associated with a decreased risk of ILI compared with taking no or other malaria prophylaxis. The reasons for this are unclear but may be related to anti-inflammatory effects, activity against bacterial respiratory pathogens, effects on disease transmission in closed populations (e.g., military deploying groups), or other unmeasured factors. With few proven strategies for decreasing ILI risk in travelers, these findings bear further investigation. Disclosures All authors: No reported disclosures.

Sign in / Sign up

Export Citation Format

Share Document