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[No title]   (Site not responding. Last check: 2007-11-01) If this option is not defined, the {cmd:simirt} command simulates only one latent trait with a number of items equal to the number of values defined in the {cmd:diff} option (at least one of these two options must be defined). If there is only one latent, {cmd:cov} is composed of the variance of this one, else, {cmd:cov} is composed of the variance of the first latent, followed by the variance of the second latent trait, and of the covariance. In a polytomous model, a modality of response is given as soon the latent trait of the individual is greater than the difficulties of this modality. anaqol.free.fr /macros/simirt.hlp   (1050 words)

Expected A Priori (EAP) Estimation of Latent Trait Scores The latent response variables are distinct from the latent trait(s); latent traits are to latent response variables what factors are to continuous measures in a standard factor analysis model. Attention is restricted to fully Gaussian latent trait models--that is, here (1) the latent trait is assumed to have a normal (or, for multiple latent traits, a multivariate normal) distribution; and (2) response functions are modeled as normal-ogives (normal cumulative distribution functions; this assumption follows from the assumption of normally distributed measurement error). In this context it refers to a posterior probability distribution of latent trait scores--specifically, the predicted distribution of scores for a given case given (a) the response pattern of that case, and (b) the estimated model parameters. ourworld.compuserve.com /homepages/jsuebersax/irt2.htm   (2332 words)

Creative Genius or Psychotic? A Strong Correlation Sternberg (2001) suggests that creativity, like intelligence, is a trait that is naturally hard to define, but can be linked by the common idea that things that are creative are both novel and high in quality, while things that are intelligent are not novel but merely high in quality. Latent Inhibition (LI) is defined as "the capacity to screen from conscious awareness stimuli previously experienced as irrelevant" (Carson, Peterson, & Higgins, 2003, p. Latent inhibition (LI) is the ability to disregard information that was previously deemed irrelevant and the extent to which previously considered information is judged irrelevant. www.personalityresearch.org /papers/byrd.html   (4979 words)

Chapter 4 As noted in Chapter 2, traits were first employed with the concept of intelligence, a phenomenon assumed to be transmitted through heredity and immune to environmental influences. Traits so defined are not causes, but simply convenient descriptions of psychological regularities that occur and may be influenced by environmental contexts. Goldberg's (1993) question of "Do traits exist?" may be rephrased as Cone's (1991) "What levels of aggregation of tests and criteria are needed to demonstrate trait properties?" To demonstrate trait consistency, it appears necessary to aggregate items, persons, and occasions of measurement. www.acsu.buffalo.edu /~stmeier/c4.html   (6323 words)

A multitrait-multisource confirmatory factor analytic approach to the construct validity of ADHD and ODD rating scales ... Unless procedures are used that allow for the separation of trait from source effects, it is difficult to know the meaning of the correlations among the three symptom dimensions as well as relations of the dimensions to other variables (e.g., academic problems, emotional problems, peer problems, conduct disorder, parenting variables, and so on). Trait effects represent the systematic variance in a specific manifest variable (e.g., ADHD-IN measure) associated with a particular latent trait (e.g., ADHD-IN trait), while source effects represent the systematic variance in a specific manifest variable (e.g., ADHD-IN measure) associated with a particular latent source (e.g., parent source). A good measure should contain a substantial amount of trait variance and, as we explain later, more trait than source variance (for the moment, we will ignore the realistic possibility that children's behavior may be situationally specific and thus fail to generalize across the home/parent source and school/teacher source situations). www.findarticles.com /p/articles/mi_m0902/is_2_33/ai_n13563135   (840 words)

[No title]   (Site not responding. Last check: 2007-11-01) In this model, the items are separated in Q groups and each group of items is linked to one and only one latent trait. Each group fits a Rasch model relatively to the corresponding latent trait, so the score computed in each group of item is a sufficient statistics of this latent trait (to a specific value of this score is associated only one value for the latent trait). To improve the time of computing, the difficulty parameters are estimated in each unidimensional Rasch model and used as an offset variable to estimate the parameters of the distribution of the multidimensional latent trait. anaqol.free.fr /macros/mmsrm.hlp   (519 words)

STATISTICS NOTICE Higher-order latent traits are proposed for specifying the joint distribution of binary attributes in models for cognitive diagnosis. This approach results in a parsimonious model for the joint distribution of a high-dimensional attribute vector that is natural in many situations when specific cognitive information is sought but a less informative item response model would be a reasonable alternative. This approach stems from viewing the attributes as the specific knowledge required for exam performance, and modeling these attributes as arising from a broadly defined latent trait resembling the latent trait of item response models. www.stat.uiuc.edu /seminar/fa02/091202.htm   (137 words)

Latent Trait Analysis and Item Response Theory (IRT) Models They are not a comprehensive guide to latent trait modeling, but only an accretion of pages and files that deal with specific aspects of the subject. Latent Trait Analysis (LTA), a form of latent structure analysis (Lazarsfeld & Henry, 1968), is used for the analysis of categorical data. If one merely wishes to develop a scale consisting of a few (3-20) items that all measure the same trait and to administer this scale to measure some trait of interest, it often is not necessary to apply latent trait models. ourworld.compuserve.com /homepages/jsuebersax/lta.htm   (1188 words)

Latent traits, measurement invariance, psychopathology, and public health: Measurement bias in tests of psychopathology ...   (Site not responding. Last check: 2007-11-01) Latent traits, measurement invariance, psychopathology, and public health: Measurement bias in tests of psychopathology and its relation to public health research Measurement bias is present when individuals equivalent on the latent trait, but from different groups, do not have identical probabilities of observed scores. At the end of the session the learner will be able to discuss: measurement bias, latent trait models for assessing measurement bias, and the realtion of measurement bias to public health research. apha.confex.com /apha/131am/techprogram/paper_67104.htm   (398 words)

Lecture 7: Does personality change over time If the time-lagged correlations are not lower than the contemporaneous correlations, this suggests that the latent trait that accounts for the relationship between the behavioural measure and the self-report measure does not change between the two assessment times. Conly (1985) had young adults rate themselves and be rated by their peers in terms of how N, Impulsive and E they were, and 20 years later got them to do self-reports again on these temperament dimensions, showed that the time-lagged heteromethod correlations were only slightly lower than the contemporaneous correlations. This means that 60-80% of the true score variance on latent traits stayed the same across 20 years. www.psy.mq.edu.au /305/change.html   (2650 words)

MPR-online 1999, Vol.4, No.2   (Site not responding. Last check: 2007-11-01) Since psychological measures usually contain large measurement errors, the correlation between the underlying latent traits should be disattenuated. Another procedure that calls for multidimensional item response models to directly estimate the variance-covariance matrix of the latent traits is also proposed. Results of simulation studies indicate that the staged estimation for the correlation between latent traits may be biased and exceed unity and the direct estimation yields unbiased parameter recovery. www.dgps.de /fachgruppen/methoden/mpr-online/issue7/art4/article.html   (154 words)

European Journal of Psychological Assessment, Vol. 16, No. 2, 2000 In a second series of analyses, the two single-construct models were combined to a multi-construct latent state-trait model in order to determine the correlation of the latent traits and the correlations between the latent state residuals of the two constructs within the same occasion of measurement. The correlation between the two traits amounted to.61 and was considerably higher than the correlations between the corresponding manifest variables. Furthermore, the within-occasion correlations of the latent state residuals are substantial, indicating that the occasion-specific effects influenced the measures of both constructs in the same direction, i.e., attachment and cohesion states fluctuate synchronously across time. www.hhpub.com /journals/ejpa/20001602.html   (1190 words)

Nutrition & Metabolism | Full text | An evaluation of the metabolic syndrome in the HyperGEN study In this study, quantitative evaluation of the MetS latent traits (q-MetS) was based on the statistical multivariate method factor analysis (FA). The trait characterized as the categorical MetS (c-MetS) was studied according to the NCEP definition; b. The underlying (latent) traits or clusters of MetS (q-MetS) were evaluated by performing FA with and without Varimax rotation on 11 risk factors. www.nutritionandmetabolism.com /content/2/1/2   (4532 words)

Limits on statistical prediction and the "Personality Coefficient" Higher correlations with personality measures are of course easy to obtain, but are dismissed as mere estimates of reliabililty e.g., correlations of particular trait measures with other measures of the same trait or the correlation of a trait between identical twins. The answer to the first question is no, it is not surprising, but merely what one would expect given most of our outcome measures are dichotomous (success/failure, act or withhold action) and that underlying latent traits do not predict outcomes, but rather the probability of an outcome. Although the underlying, latent distribution in all of these simulations is normal, it is interesting to note that the distribution of the aggregated scores approaches a rectangular distribution. personality-project.org /perproj/theory/personalitycoefficient.html   (844 words)

Measurement Processes The term "ipsative" (sometimes seen as ipsitive [sic.]) is based on "ipso facto" which means "by the very fact itself, the very fact." In this usage, ipsative measurement means measurement against itself. This form of measurement frequently focuses on hidden, or latent traits that are not "known" to the individual such as those in personality instruments. One knows that the individual reports more association with the indicators of one trait rather than another, but self-reporting twice as many indicators does not mean that the level of a trait is twice as high. www.documentingexcellence.com /stat_tool/measurement_processes.htm   (956 words)

IRT Models For Unfolding -- Publications Andrich, D. A hyperbolic cosine latent trait model for unfolding polytomous responses: Reconciling Thurstone and Likert methodologies. Andrich, D. Hyperbolic cosine latent trait models for unfolding direct responses and pairwise preferences. Hoijtink, H. A latent trait model for dichotomous choice data. www.psychology.gatech.edu /unfolding/Publications.html   (1030 words)

Probit Latent Class Analysis with Dichotomous or Ordered Category Measures: Conditional Independence/Dependence Models ...   (Site not responding. Last check: 2007-11-01) Within a latent class, conditional dependence is modeled as latent trait, and latent distribution analysis can be viewed as special cases of the mixed latent trait model. apm.sagepub.com /cgi/content/abstract/23/4/283   (142 words)

Book: New Developments in Categorical Data Analysis for the Social and Behavioral Sciences (Hardcover)   (Site not responding. Last check: 2007-11-01) This new book is a collection of up-to-date studies on modern categorical data analysis methods, emphasizing their application to relevant and interesting data sets. Latent class analysis yields the classification of a group of respondents according to their pattern of scores on the categorical variables. After a method is explained, the potential of the method for analyzing categorical data is illustrated by means of a real data example to show how it can be used effectively for solving a real data problem. www.assess.com /Books/b-47286.htm   (495 words)

Latent Personality Traits - HERO GAMES Discussion Boards Latent Personality Traits - HERO GAMES Discussion Boards However, it also gives her an accidental change (14-) to the "storm queen persona" if she pushes her powers the storm queen (who is far more powerful and can also affect weather) takes over - this, as her teammates know from experience, is Extremely Bad (TM)). However, I wanted to model the fact that, when the character is tired, or under duress, or simply letting her guard down, the storm queen can nudge her impulses and cause uncharacteristic personality traits to come to the fore (not take over, per say). www.herogames.com /forums/showthread.php?t=32546   (379 words)

Taxometric Workshops   (Site not responding. Last check: 2007-11-01) Multivariate taxometric procedures are increasingly being used in the social and biological sciences to test competing models of latent structure. These procedures are uniquely suited for determining whether a pool of indicators measure a latent dimensional (latent factors, latent traits) or typological (natural kinds, classes, nonarbitrary clusters) construct. In this workshop, participants will be introduced to the underlying rationale of multivariate taxometrics through lectures and worked exercises with taxometric software. www.vanderbilt.edu /quantmetheval/Taxometrics/workshops.html   (857 words)

Welcome to the XXV International Congress of Applied Psychology   (Site not responding. Last check: 2007-11-01) Three levels of item number constraint and three levels of item exposure rater control were manipulated under four kinds of correlations between latent traits. MAT yields more precise measures of ability than unidimensional CAT by utilizing the correlations between latent traits. MAT is suitable in between-item multidimensional tests, such as test batteries, multiple achievement or aptitude tests, personality inventories, and within-item multidimensional tests, such as performance-based tests, and tests with items measuring more than one dimension simultaneously. www.iaapsy.org /25icap/common/OP961.htm   (285 words)

Brain white matter lesions detected by magnetic resosnance imaging are associated with balance and gait speed -- Starr ... to construct and test latent trait models of association among All correlations reflect a worsening in outcome compared with the latent traits. There was a sizeable association between the two latent traits jnnp.bmjjournals.com /cgi/content/full/74/1/94   (3847 words)

Procedures - MML Ordinal Tables- References   (Site not responding. Last check: 2007-11-01) Cohen, J. Subgroup Comparisons of Partially Measured Latent Traits. Mislevy, R. Randomization-based inference about latent variables from complex samples. Zavoira, T., & McElvey, W. A statistical model for the analysis of ordinal level dependent variables. am.air.org /help/NAEPTextbook/htm/rmmlordinaltables.htm   (51 words)

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