bluuebunny/crossref_metadata_2025 huggingface dataset:
The evidence base to select a method for assessing glaucomatous visual field progression
Authors: Ernest Paul J. G. , Schouten Jan S. A. G. , Beckers Henny J. M. , Hendrikse Fred , Prins Martin H. , Webers Carroll A. B.
Published: August 2011

A large number of methods have been developed for assessing glaucomatous visual field progression, but their properties have not yet been systematically evaluated. In this systematic literature review, we summarize the evidence base for selecting a method by providing answers to ten relevant questions on the variety, validity and reproducibility of methods. In total, we found 301 different methods in 412 articles. The majority of studies (54%) used the Humphrey Field Analyzer. No data have been published about the reproducibility of methods. Although there is no gold standard to assess glaucomatous visual field progression, we found evidence on validity for 48 different methods. Some methods were less capable of distinguishing between progressive and nonprogressive patients. Choosing among twelve methods is supported by some evidence of their validity. These methods still differ in sensitivity, specificity and predictive values of test results within studies comparing several methods. In conclusion, the current evidence base is not perfect. A selection should be made from a limited number of methods, according to the clinical purpose of progression assessment. Methods that quantify the rate of visual field progression seem to be the most appropriate for guiding subsequent medical actions in individual patients. Future studies should investigate whether using one method to monitor patients is superior to another method in preventing loss of quality of life.
Augmenting Cognitive Architectures to Support Diagrammatic Imagination
Authors: Chandrasekaran Balakrishnan , Banerjee Bonny , Kurup Unmesh , Lele Omkar
Published: August 2011

Diagrams are a form of spatial representation that supports reasoning and problem solving. Even when diagrams are external, not to mention when there are no external representations, problem solving often calls for internal representations, that is, representations in cognition, of diagrammatic elements and internal perceptions on them. General cognitive architectures—Soar and ACT‐R, to name the most prominent—do not have representations and operations to support diagrammatic reasoning. In this article, we examine some requirements for such internal representations and processes in cognitive architectures. We discuss the degree to which DRS, our earlier proposal for such an internal representation for diagrams, meets these requirements. In DRS, the diagrams are not raw images, but a composition of objects that can be individuated and thus symbolized, while, unlike traditional symbols, the referent of the symbol is an object that retains its perceptual essence, namely, its spatiality. This duality provides a way to resolve what anti‐imagists thought was a contradiction in mental imagery: the compositionality of mental images that seemed to be unique to symbol systems, and their support of a perceptual experience of images and some types of perception on them. We briefly review the use of DRS to augment Soar and ACT‐R with a diagrammatic representation component. We identify issues for further research.
Ultrasonographic examination of the palmar/plantar aspect of the fetlock in the horse: Technique and normal images
Authors: Seignour M. , Coudry V. , Norris R. , Denoix J‐M.
Published: August 2011

The purpose of this paper is to present a comprehensive ultrasonographic technique to image the palmar/plantar aspect of the fetlock in the horse, from themanica flexoria(MF) down to the base of the proximal sesamoid bones (PSBs) and to describe the normal images. Ultrasonography, in combination with radiography, is the technique of choice to identify and document tendon and ligament injuries in routine practice and has been shown adequate for evaluating the palmar/plantar aspect of the fetlock. Detailed descriptions of transverse and longitudinal sections performed on the weightbearing or flexed limb are provided, as well as the technique for dynamic examination of the area. A thorough knowledge of detailed ultrasonographic anatomy is critical to identify abnormal images and establish an accurate diagnosis of palmar/plantar fetlock injuries.
THE MULTIFACTORIAL THEORY OF INHERITANCE AND ITS APPLICATION TO INTELLIGENCE1
Authors: BURT CYRIL , HOWARD MARGARET
Published: August 2011

Abstract. The hypothesis put forward for discussion is that, among normal persons, differences in “intelligence” (i.e., innate general cognitive ability) are determined by a large number of genes, segregating in accordance with Mendelian principles and each producing effects that are small, similar, and cumulative. From these assumptions, with a due allowance for dominance and assortative mating, formulae are derived for the correlations to be expected between siblings, parents and offspring, and remoter relatives. Data from school surveys yield coefficients which are in almost complete agreement with the theoretical figures thus deduced. An attempt is also made to analyse the variance of the assessments obtained, and to estimate the contributions of genetic factors and non‐genetic factors respectively. Appreciable differences are found between the results obtained from raw measurements based directly on intelligence tests and those obtained from revised or adjusted assessments based on all the available evidence. With the former nearly 25 per cent. of the variance is apparently due to non‐genetic factors; with the latter barely half that amount.
CLASS DIFFERENCES IN GENERAL INTELLIGENCE: II
Authors: Conway J.
Published: August 2011

The investigations carried out by Dr. Halsey and his co‐workers have revealed appreciable differences between the averages obtained by pupils from different socio‐economic classes in tests of ‘intelligence’ at the 11+ examination. In their view, however, the class‐differences thus indicated are the result solely of differences in environmental conditions. The following paper maintains that they are largely, though not wholly, due to differences in genetic constitution. The criticisms advanced by Dr. Halsey against the genetic theory are examined in detail, and appear to arise partly from erroneous theoretical assumptions and partly from inadequate data.
RELIABILITIES AND VALIDITIES OF SIMPLE AND EXTENDED WEIGHTED AND BUFFERED UNIFACTOR SCALES
Authors: Cattell Raymond B. , Radcliffe John A.
Published: August 2011

Formulae are required for estimating the reliability and validity of scales constructed to measure a single factor, when irrelevant common and specific factors also exist among the data. Equations are here developed for this purpose, to cover scales with single members or many members, and with both weighted and unweighted components: the use of suppressor patterns is also taken into account. Relations to existing formulae, e.g., those of Spearman and Brown, are worked out, and an improved nomenclature is proposed.
A FACTORIAL STUDY OF VALUE JUDGEMENTS AMONG ADOLESCENT GIRLS
Authors: Hallworth H. J. , Waite G.
Published: August 2011

The following paper reports an experimental study of what is, for brevity, termed ‘evaluation’—i.e., the degree of approval or disapproval accorded by the subjects tested to certain familiar concepts, such as ‘honesty’, ‘kindness’, ‘pleasure’, ‘money’, ‘religion’, and the like. The method used was a ‘semantic differential’ test, given to 128 girls aged 14 to 15. Forty‐eight concepts were presented for evaluation, and seven evaluative scales—each with seven grades or points—were used. The mean evaluative scores for each concept were correlated over all the persons tested. The correlation matrix was analysed by the method of principal components; this furnished a first component which was identified as a factor of ‘general evaluation’. A rotation according to the Varimax criterion was then applied, and yielded five orthogonal factors which apportioned the variance more evenly. A psychological interpretation is suggested for each of these factors so obtained.
THE INTERACTION OF HEREDITARY AND ENVIRONMENTAL INFLUENCES1
Authors: Cattell Raymond B.
Published: August 2011

This paper is concerned with improvements in the multiple abstract variance analysis method (MAVA). The assumptions of the latter are more clearly developed and implications for genetic, psychological, and sociological research issues are discussed. The main conclusion is that although it offers solutions to questions not answerable by twin study methods, or by current experimental designs related to learning theory, to personality theory and to important sociological issues, MAVA demands much larger and more carefully planned and highly organized research programmes than have hitherto been contemplated in psychology.
PROMAX: A QUICK METHOD FOR ROTATION TO OBLIQUE SIMPLE STRUCTURE
Authors: Hendrickson Alan E. , White Paul Owen
Published: August 2011

A new method for analytical rotation to oblique simple structure is described. Orthogonal simple structure is achieved by means of any of several existing rotation methods and this is then transformed into an oblique solution.
TESTING DIFFERENCES BETWEEN RELIABILITY COEFFICIENTS1
Authors: Kristof Walter
Published: August 2011

In the following paper an attempt is made to derive a working formula, based on the method of maximum likelihood, for testing the significance of the difference between two reliability coefficients. It is assumed that both tests have been administered to the same group, and can be split into equivalent halves. A worked example is appended by way of illustration.
THE TEST‐RETEST RELIABILITY OF SOME METHODS OF MULTIPLE COMPARISON1
Authors: Slater Patrick
Published: August 2011

Four experiments were made to study the relative reliability of ranking, paired comparison and comparison in sets of three or more, for recording personal preferences. The whole weight of the evidence is in favour of the view that an informant, when expressing his personal preferences, tends to maintain a level of reliability which characterizes him as an individual and is unaffected by variations in the number of objects he is given to compare or changes in the methods he is asked to use.
NOTES ON THE ANALYSIS OF MIXED FREQUENCY1 DISTRIBUTIONS
Authors: Cox D. R.
Published: August 2011

Some general aspects of the analysis of mixtures of distributions are reviewed. For the analysis of some data of D. E. Broadbent a particular method is proposed and illustrated. In an appendix the convolution of log normal distributions is considered.
MULTIPLE REINFORCEMENT EFFECTS IN SHORT‐TERM MEMORY
Authors: Brelsford J. W. , Shiffrin R. M. , Atkinson R. C.
Published: August 2011

A continuous memorizing situation was studied in which test and study trials alternated throughout an experimental session. The items studied were paired‐associates. The interval between study and test for a particular item was randomly determined; and an item was given one, two, three or four reinforcements. A quantitative model is proposed which has two memory stores: a short‐term store in which the subject generates a carefully controlled rehearsal scheme of fixed length, and a long‐term store in which information is accumulated and lost. A large number of theoretical predictions of the model were verified quantitatively by the data, which confirm results of previous experiments, and support the hypothesis that highly structured rehearsal schemes play a major role in many short‐term memory and learning situations.
NEW METHODS IN MAXIMUM LIKELIHOOD FACTOR ANALYSIS
Authors: Jöreskog K. G. , Lawley D. N.
Published: August 2011

Until recently the main difficulty in the use of maximum‐likelihood estimation in factor analysis has been the lack of satisfactory methods of obtaining numerical solutions. This defect has now been remedied, and this paper describes new rapid methods of finding maximum‐likelihood estimates.
MOMENTS OF THE STATISTICS KAPPA AND WEIGHTED KAPPA
Authors: Everitt B. S.
Published: August 2011

This paper considers the mean and variance of the two statistics, kappa and weighted kappa, which are useful in measuring agreement between two raters, in the situation where they independently allocate a sample of subjects to a prearranged set of categories.
TESTS OF SIGNIFICANCE IN TWO‐WAY DESIGNS (MIXED MODEL) WITH DICHOTOMOUS DATA
Authors: Gabrielsson Alf , Seeger Paul
Published: August 2011

Computer simulation experiments are performed to investigate the applicability of different tests of treatment and interaction effects in mixed two‐way designs with dichotomous data. The main results are that the F test can be used with good approximation as a test of equal treatment effects, except for strongly asymmetric populations, and that the F test may be used with some caution as a test of no interaction.
ON SUBJECTIVE PROBABILITY REVISION
Authors: Morgan Byron J. T.
Published: August 2011

A simple one‐parameter model is proposed for the behaviour of conservative subjects in a probability revision task. The model exhibits several features of experimental data, makes specific predictions and provides a useful norm in a somewhat confused and inconsistent area of research.
THE EFFECT OF NON‐NORMALITY ON THE SAMPLING DISTRIBUTION AND STANDARD ERROR OF RELIABILITY COEFFICIENT ESTIMATES UNDER AN ANALYSIS OF VARIANCE MODEL
Authors: Bay Kyung S.
Published: August 2011

Although the calculated reliability of a test based on a small sample of subjects is an estimate of the population reliability and, hence, is subject to sampling fluctuation, little application has been made of statistical inference techniques to the reliability coefficient. The need for such techniques was recognized as early as the 1940s, and a few attempts have been made to introduce analysis of variance (anova) procedures and to relate the sampling distribution of reliability coefficient estimates to the well‐known F distribution (e.g. Jackson & Ferguson, 1941; Ebel, 1951). It was, however, Kristof (1963) who first presented a rather complete sampling theory of reliability estimates and a method to apply it. Feldt (1965) derived similar results based on an anova model and applied it to a binary item test case. The above sampling theories were based on normality assumptions regarding the true and error score distributions. It is, however, conceivable that real data will not always meet the rigorous assumption of normality, and yet very little is known about the effects of non‐normality on the sampling distribution of reliability estimates. The present paper contains the results of an investigation of the effects of non‐normality under a mixed model anova. Both analytical and computer simulation methods are used.
CONFIDENCE INTERVALS FOR MULTIPLE COMPARISONS AND THE MISUSE OF THE BONFERRONI INEQUALITY
Authors: Rodger R. S.
Published: August 2011

The Bonferroni inequality can be used to derive a value of Student's t (or a unit normal z) for confidence intervals, and guarantees that the probability is at least 1 — a that all intervals for m contrasts, chosen in advance, cover the true values of their contrasts. An attempt has been made to extend this technique to contrasts chosen post hoc. It is shown that this extension is not generally valid.
ON THE STABILITY OF ROTATED FACTOR LOADINGS: THE WEXLER PHENOMENON
Authors: Jennrich Robert I.
Published: August 2011

The formulae which give the standard errors of factor loading estimates, while available and computable, are complicated and our understanding of them is limited. A non‐technical description of their behaviour under favourable and unfavourable conditions is given. Of particular interest is their behaviour in the presence of singularities arising from equal eigenvalues and undefined rotation.
MONOZYGOTIC AND DIZYGOTIC TWINS REARED TOGETHER: SENSITIVITY OF HERITABILITY ESTIMATES
Authors: Hogarth Robin M.
Published: August 2011

This paper examines the method of estimating the heritable component of behavioural traits by comparing observed similarities between pairs of MZ (monozygotic) twins as opposed to DZ (dizygotic) twins. The technique of sensitivity analysis is used to investigate the importance of assumptions made to calculate heritability estimates. This permits not only the investigation of specific assumptions, but also the effects of different combinations of assumptions. The assumptions examined include: the level of assortative mating, degree of intra‐pair environmental similarity of MZ as opposed to DZ twins, and the presence of genotype‐environment covariance. It is noted that estimates of genetic variance—although large—are sensitive to small changes in these assumptions, and that different combinations of assumptions can produce similar estimates of genetic variance. Although this work is effected within the classical twin method, its implications are also valid for more sophisticated analyses of the ‘nature‐nurture’ problem.
AN APPLICATION OF LATENT TRAIT MENTAL TEST THEORY
Authors: Jensema Carl J.
Published: August 2011

Solutions were sought for problems in applying the Birnbaum three‐parameter logistic mental test model through Bayesian tailored testing. Both empirical and Monte Carlo data were utilized. The general conclusions were: (1) Although conventional tests are not generally good for tailored testing, some individual items are excellent. (2) It may be possible to develop methods of graphic parameter estimation to the point where expensive maximum‐likelihood methods can be by‐passed. (3) An item bank for tailored testing must have a sufficiently large number of items whose difficulties are uniformly distributed and whose discriminatory powers are high. (4) The use of prior information in Bayesian tailored testing does not lead to a substantial reduction in the number of items needed, unless prior information is unrealistically accurate. (5) The standard error of the estimate of ability has certain characteristics which may have important consequences for tailored testing under certain conditions.
A SCALING FORMULA FOR BOUNDED MARK INTERVALS
Authors: Tluanga L. N.
Published: August 2011

The paper deals with the adjustment of examiners’ marks for a single test when the scripts are marked by several independent examiners, each of whom is assigned a different but statistically equivalent set of scripts.
GRADIENT METHODS FOR ANALYTIC ROTATION
Authors: Browne M. W.
Published: August 2011

Gradient methods are employed in orthogonal and oblique analytic rotation. Constraints are imposed on the elements of the transformation matrix by means of reparameterizations.
A DERIVATION OF THE HESSIAN OF THE (CONCENTRATED) LIKELIHOOD FUNCTION OF THE FACTOR MODEL EMPLOYING THE SCHUR PRODUCT
Authors: Neudecker H.
Published: August 2011

An expression is derived for the Hessian of the (concentrated) likelihood function of the factor model, employing matrix differential calculus in conjunction with the Schur product. Hence the results of Clarke (1970) are achieved by an alternative route.
A MATHEMATICAL MODEL FOR CONFLICTING JUDGEMENTS CAUSED BY STRESS, APPLIED TO POSSIBLE MISESTIMATIONS OF SPEED CAUSED BY ALCOHOL
Authors: Zeeman E. C.
Published: August 2011

A mathematical model is proposed, based on catastrophe theory, to describe the qualitative effect of stress upon the neural mechanisms used for making judgements, such as estimating speed. The model is used quantitatively to fit data, and to explain the cusp‐shaped results of Drew et al. (1959), showing that introverts under alcohol tend to drive either too fast or too slow in a driving simulator. Experiments are suggested in which discontinuous jumps in perception of continuous variables like speed might well appear.
THE UNIFORM DISTRIBUTION IN SIGNAL DETECTION THEORY
Authors: Morgan Dr.Byron J. T.
Published: August 2011

The robustness of signal detection theory (SDT) is investigated with respect to the form of the underlying distributions. Usually these distributions are taken to be normal; here an SDT model based on two overlapping uniform (rectangular) distributions is examined, for the Yes/No experiment and the rating‐method experiment. In the Yes/No case the SDT measure (using uniform distributions) is found to be equivalent to a measure recently proposed by Hammerton & Altham (1971), and, from contingency‐table considerations, it is a measure likely to give similar conclusions to the SDT measure using normal distributions. In the rating‐method case it is surprising to find that the SDT model with uniform distributions yields non‐significant goodness‐of‐fit statistics for many sets of data.
‘HARK‐BACK’: A SIMPLE MEASURE OF SEARCH PATTERNS
Authors: Green T. R. G. , Jackson P. R.
Published: August 2011

A measure is described which attempts to quantify one aspect of search behaviour, namely, the frequency of referring back to earlier parts of the search pattern or ‘harking back’. In a dialogue, harking back corresponds to bringing a topic up again when it was mentioned earlier; in a problem‐solving task, it corresponds to putting aside one line and picking up again from an earlier position. The coefficient of hark‐back may be interpreted variously as a measure of the working style, of the complexity of information‐processing, or of the searcher's inherent limitations, depending upon the nature of the task. Analysis of data from an interviewing study, where harking back was deemed to show complex decision‐making, gave encouraging results.
FORMALIZING THEORIES OF STUTTERING
Authors: Still A. W. , Sherrard Carol A.
Published: August 2011

Stuttered speech may be reduced to a sequence of stuttered and non‐stuttered words, and is then readily amenable to statistical analysis. We attempt to state versions of the anxiety, feedback, and conflict theories of stuttering as mathematical models which may be tested against the structure of sequences of stuttered and non‐stuttered words. In this way we hope to produce a means of deciding between the many theories of stuttering. Data from a single subject are used to illustrate the method.
Fitting the Rasch model—A heady tale
Authors: Wood Robert
Published: August 2011

It is shown that the Rasch model fits simulated coin‐tossing data very well. An explanation is offered and in the ensuing discussion issues concerning the fitting of latent trait models are raised.
Approximate expressions for parameter estimates in the Rasch model
Authors: Cohen Leslie
Published: August 2011

The Wright‐Panchapakesan (1969) maximum‐likelihood equations for estimating the ability and difficulty parameters in the Rasch model have hitherto required an iterative procedure for their solution. In this paper the equations are solved approximately and simple closed forms are established which give values close enough for most practical purposes to those obtained by iteration. The results are illustrated with reference to a 50‐item physics test.
A comparison of approaches to the analysis of longitudinal categoric data
Authors: Plewis Ian
Published: August 2011

Marascuilo & Serlin (1979) discuss the problem of measuring relative change for a dichotomous variable and suggest ways of testing for the statistical significance of such changes. This article considers alternatives to the non‐parametric approach adopted by Marascuilo & Serlin, alternatives which emphasize statistical models and which can be extended to all types of longitudinal categoric data. The models are fitted to the data presented by Marascuilo & Serlin, the results are compared and the advantages and disadvantages of the various approaches are discussed.
Generalizability theory: 1973–1980
Authors: Shavelson Richard J. , Webb Noreen M.
Published: August 2011

This paper reviews the developments in generalizability theory from 1973 to 1980. The first section presents a sketch of generalizability theory. The second section reviews theoretical contributions about (1) problems associated with estimating variance components, including sampling variability and negative estimates, (2) fixed facets, (3) criterion‐referenced measurement, (4) symmetry, (5) multivariate generalizability, and (6) sampling in observational measurement. The final section presents an illustrative application of generalizability theory, including univariate and multivariate generalizability analyses of balanced and unbalanced designs, and Bayesian estimation of variance components.
A closed sequential procedure for comparing the binomial distribution to a standard
Authors: Wilcox Rand R.
Published: August 2011

Fhanér (1974) proposed an approach to measuring achievement where the binomial error model is assumed, and where the goal is to determine whether an examinee's per cent correct true score is above or below a known constant. Wilcox (19806), as well as van den Brink & Koele (1980), point out that a substantially larger number of items might be required when guessing is incorporated into Fhanér's solution. The purpose of this brief note is to derive the exact sampling distribution of a closed sequential procedure that solves the problem considered by Fhanér. We then show that the probability of a correct decision under the new procedure is exactly the same as it is when Fhanér's procedure is applied. In addition, the number of observations under the closed sequential procedure is always less than or equal to the number required under the fixed sample size approach. In some cases, the number of observations is considerably less.
The approximate randomization test as an alternative to the F test in analysis of variance
Authors: Still A. W. , White A. P.
Published: August 2011

In experimental psychology it is usually difficult to show that populations sampled meet the requirements for the use of t or F tests, or even that they are similar to populations sampled in Monte Carlo experiments designed to demonstrate the robustness of these parametric tests. Consequently, a test which makes weaker requirements without sacrificing power or versatility should be preferred. It is shown that this is true of modified approximate randomization tests, which, like the randomization tests on which they are based, use observed scores to set up a sampling distribution. The tests are versatile, since they can be used on factorial designs of any complexity and the results of Monte Carlo experiments indicate that their power approximates that of the F test when the assumptions underlying the latter are met and is significantly greater when the populations sampled are made up of two normal distributions with different means. It is concluded that, where adequate computing facilities are available, the approximate randomization test is preferable to an F test for analysis of variance designs.
The correlation between variate values and ranks in small size samples
Authors: O'Brien Robert M.
Published: August 2011

The average product moment correlation between randomly sampled variate values and their ranks is estimated for small size samples from 10 different distributions. We find that these correlations are generally quite high and approach the limiting values reported by Stuart (1954, 1955) as the sample size increases. These findings have implications for the use of rank‐order values as measures of underlying variate values when the sample size is small.
Letter transpositions in words: Application of a fixed‐constraint model
Authors: Jones Gregory V.
Published: August 2011

Considerable recent work has been devoted to investigation of the occurrence and effects of letter transpositions within words. Their occurrence has been studied in disorders of reading and writing, and their effects studied experimentally using for example lexical decision tasks. With the publication of empirically compiled tables of anagrammatic frequencies it becomes possible to test a model of the distributions of orthographically defined words of this type. The model rests upon the simplifying assumption that the constraint imposed by the specification of each letter of each verbal item may be taken as fixed.
On a closed sequential procedure for categorical data, and tests for equiprobable cells
Authors: Wilcox Rand R.
Published: August 2011

Cacoullos & Sobel (1966) proposed a closed sequential procedure for identifying the cell probability in a multinomial distribution that has the largest value. They showed, inter alia, that their sequential procedure has certain advantages over the fixed sample size procedure of Bechhofer et al. (1959). This paper extends this procedure in two directions. First, moments of the probability function are written in terms of the tail probability of a negative multinomial distribution. This makes it a relatively simple matter to determine the moments in certain important special cases. Second, an exact test for equiprobable cells is proposed, and certain properties of the test are established. In particular, the test is shown to be unbiased in the sense of majorization.
Testing for differences between means with ordered hypotheses
Authors: Macdonald Ranald R. , Smith Philip T.
Published: August 2011

A technique for incorporating an experimenter's predictions of orderings of the treatment means into an analysis of variance testing procedure is presented. The experimenter's predictions are assessed in terms of a statistic based on the ordering of the means (e.g. Kendall's tau). The product of the significances of this statistic and of F is used to obtain the significance level. In comparison with other approaches simulations show this to be the most appropriate technique where the experimenter can predict the order of the treatment means but wishes to have reasonable power even if the predicted ordering is wrong.
Non‐linear canonical correlation†
Authors: van der Burg Eeke , de Leeuw Jan
Published: August 2011

Non‐linear canonical correlation analysis is a method for canonical correlation analysis with optimal scaling features. The method fits many kinds of discrete data. The different parameters are solved for in an alternating least squares way and the corresponding program is called CANALS. An application of CANALS is discussed and also a study of the stability of the scaling results.
Some non‐parametric tests for analysing ranked data in multi‐group repeated measures designs
Authors: Katz Barry M. , McSweeney Maryellen
Published: August 2011

This paper develops two statistical techniques for analysing ranked data. The first technique can be used in designs in which c independent groups of subjects are asked to rank order p objects with respect to a specified criterion. An explicit statement of a statistic which can be used to determine whether differences in ranking patterns exist between the groups is presented together with associated post hoc procedures. The statistic is a generalization of a technique developed by Hollander & Sethuraman (1978). The second technique developed can be used in designs in which subjects in c independent groups are each asked to rank order a set of p items with respect to a certain criterion under q different conditions of ranking. An explicit statement of a statistic which can be used to test the groups by items by conditions three‐way interaction hypothesis is presented together with an analysis strategy for testing the other effects of interest.
Independence of slope and intercept in Sternberg's memory‐scanning paradigm
Authors: Valentine John , Wilding John , Mohindra Naresh
Published: August 2011

Negative correlations have been obtained over subjects between slopes and intercepts in memoryscanning tasks. It is argued that such correlations are to be expected on purely statistical grounds. Predictions for such correlations are derived and compared with data from a large scale experiment of this type. A satisfactory match is obtained.
The weak Borda effect and plurality–majority disagreement
Authors: Colman Andrew M.
Published: August 2011

The weak Borda effect indicates a failure on the part of the plurality voting procedure to satisfy a criterion of reasonableness according to which none of the losers should be preferred to the winner by a majority of the voters. Contrary to the interpretation of a recent critic, it is not claimed that the weak Borda effect necessarily indicates plurality–majority disagreement. To minimize future misunderstanding, formal definitions of the plurality procedure, the weak Borda effect, and plurality–majority disagreement are given, and a simple method is derived for evaluating the exact probability of plurality–majority disagreement in small decision‐making committees.
Planned comparisons: Controlling power and determining sample sizes
Authors: Wilcox Rand R. , Chao Eddie
Published: August 2011

The problem of power in planned comparisons with unequal sample sizes and unequal variances is considered. An exact method of controlling power and deciding whether the sample sizes are large enough is provided.
The statistical analysis of a model for storage and retrieval processes in human memory
Authors: Batchelder William H. , Riefer David M.
Published: August 2011

The statistical theory is developed for a simple model, originally presented by Batchelder & Riefer (1980), that is capable of separately measuring storage and retrieval processes in human memory. The model is intended for use by researchers who have hypotheses about the effects of independent variables on storage and retrieval that are general enough not to demand any particular human memory paradigm for their test. In Section 1, the statistical model is presented in detail, along with an experimental paradigm for collecting data to be analysed by the model. In Section 2, parameter estimation for the model is provided assuming independent observations under constant conditions. Confidence regions for the parameters are also provided. In Section 3, hypothesis‐testing methods based on the likelihood ratio method are developed for a variety of hypotheses in the case where observations are available from several experimental conditions. These methods are also illustrated with a data set. In the conclusion, the relative advantages of the statistical model over traditional methods for studying storage and retrieval are discussed. Specifically, an example is presented where the traditional ANOVA approach yields very misleading conclusions.
Identification problems in latent trait models
Authors: Moran P. A. P.
Published: August 2011

It is shown that in the two‐parameter Birnbaum latent trait model, all the parameters are identifiable under wide conditions, provided the number of items exceeds two, and all the slopes are strictly positive.
A condition for the regression predictor to be consistent in a single common factor model
Authors: Kano Yutaka
Published: August 2011

This paper investigates the prediction of a common factor in a single common factor model with infinite items when the structural parameter vector (factor loadings and unique variances) is unknown. A condition in terms of the sample size n and the number of items p is established under which the regression predictor for a unique common factor, in which the parameter vector is replaced by the least squares estimator, converges to it in quadratic mean. The condition is that p → ∞ and p2/n → 0 under some mild assumptions.
Smoothing the joint and marginal distributions of scored two‐way contingency tables in test equating
Authors: Rosenbaum Paul R. , Thayer Dorothy
Published: August 2011

If the row and column variables of a two‐way contingency table have numerical scores, then the table is said to be scored. Scored contingency tables play an important role in equating two exams containing common items: the tables are typically quite large, and often relatively sparse, and exhibit strong positive dependence. For equating, stable, monotone estimates are required for the conditional distribution of the score on the new items given the score on the common items. We obtain such‐estimates by using generalized log‐linear models in a new way: we smooth both the interior and the margins of the two‐way table, yielding the smoothest joint distribution on the table having the same low‐order moments as the observed sample.
On the performance and stability of human metronome‐synchronization strategies
Authors: Hary David , Moore George P.
Published: August 2011

The stability of linear metronome‐synchronization strategies is tested by studying the analytic properties of synchronization error sequences. Strategies based on the time of the metronome events are generally stable, even without error‐correcting feedback. Strategies based exclusively on the timing of the subject's own tap are generally unstable even when they employ corrective feedback processes.
Iterative maximum‐likelihood estimation of parameters of the Toeplitz correlation structure
Authors: Mukherjee Bishwa Nath , Maiti Sadhan Samar
Published: August 2011

A simple iterative algorithm is proposed for obtaining the maximum‐likelihood estimates (m.l.e.) of the parameters of the symmetric Toeplitz or Laurent correlation matrix. A numerical example based on real‐life data is provided to illustrate the computation involved in the estimation and to demonstrate the feasibility of the proposed algorithm. This paper also provides expression in explicit form for the computation of the asymptotic dispersion matrix of the MLE. For comparative purposes, the Toeplitz correlation hypothesis as also other structural hypotheses have been tested and the results are discussed. The use of the proposed method in estimating the elements of Σ in the first step and then the possibility of using this estimated Σ for deriving a generalized least square estimate of the regression coefficients is pointed out.
The sensitivity of latent trait analysis to choice of prior distribution
Authors: Bartholomew D. J.
Published: August 2011

Random effects latent trait models involve an arbitrary assumption about the form of the prior distribution of the latent variable(s). Although the form of the analysis does not depend on this assumption, it does affect the estimates of the parameters. It is therefore important to know whether the values of the estimates obtained are sensitive to the choice made. This question is answered mainly by providing numerical evidence that the effect of the prior on the expected one‐ and two‐way marginal proportions is negligible.
Tests and intervals in multiple choice tests: A modification of the simplest classical model
Authors: Andrés A. Martín , del Castillo J. D. Luna
Published: August 2011

When a multiple choice test is carried out, each student is set the same series of questions composed of two or more alternatives, only one of which is correct, and from which he or she must choose only one. The simplest and most common criterion for deciding what a student knows is based on a sole and minimum quota for all the students of the total number of right answers; this criterion derives from the assumption that the student, when he or she does not know the correct answer to a question, answers any of the possible alternatives with equal probability.

In this paper, the authors show that this method may be unsatisfactory if the student is unable to imitate random selection, and they put forward an alternative model which allows one to find an estimator for the student's level of knowledge that depends on the sum of the proportions of correct answers of each type and on the total number of each type which the student gives. Likewise, they give a hypothesis test for verifying the model, two methods for finding confidence intervals for the student's level of knowledge, and three hypothesis tests for awarding a mark for it.

Numerical calculations show how inefficient the usual multiple choice tests are (100 or 150 questions with five alternative answers each) for ascertaining the student's level of knowledge.
Latent class analysis with ordered latent classe
Authors: Croon Marcel
Published: August 2011

In this paper a latent class model is described in which the latent classes are ordered imposing inequality constraints on item response and cumulative response probabilities from subsequent latent classes. These inequality constraints are derived from the basic assumption that, when the latent classes may be ordered from low to high along the latent continuum, the probability of a ‘positive’ response should increase monotonically as one moves along this continuum. An algorithm to obtain the maximum likelihood estimates of the model parameters is proposed and is applied to a real data set.
Sufficient conditions for rotational uniqueness in the additive MTMM model
Authors: Millsap Roger E.
Published: August 2011

Confirmatory factor analysis is widely used in the analysis of multitrait‐multimethod (MTMM) matrices. Sufficient conditions for rotational uniqueness in the additive MTMM model have not been fully discussed in the literature. A theorem giving sufficient conditions for uniqueness in the additive MTMM model is presented. This theorem reformulates the conditions given by Anderson & Rubin (1956), Howe (1955), and Jöreskog (1979) for the general confirmatory factor analysis model. Several corollaries of the theorem describe special cases of the additive MTMM model that will always be rotationally unique. One of these cases is illustrated with an example using real data. Some implications of these results are discussed.
Comparing the medians of dependent groups
Authors: Wilcox Rand R.
Published: August 2011

Investigations of the characteristics of real data indicate that psychometric measures can have highly skewed distributions with heavy tails and outliers. In terms of power, the paired t test is known to be unsatisfactory when distributions have heavy tails, and there is the issue of whether some measure of location, other than the mean, might be more appropriate when distributions are skewed. This paper proposes a method for comparing the medians of two dependent groups. Simulations indicate that the proposed procedure controls the probability of a Type I error to a reasonable degree. In terms of power, the new procedure is much less affected by contamination than the paired t test or the Wilcoxon signed rank test. Brief consideration is also given to an extension of the proposed procedure to more than two groups.
The psychophysical method of limits: What actually happens in a nonlinear context?
Authors: Gregson Robert A. M.
Published: August 2011

The details of response distributions in the method of limits are known to violate both simple assumptions of monotone increasing stimulus–response functions, and the derived idea that change points on such functions, those points where sensory phenomenology changes abruptly, are strictly ordered correspondingly. The predictions of nonlinear psychophysics include mappings from responses back onto stimuli which are not single‐valued. Such predictions imply that outliers to change point distributions expressed in physical units will exist under some conditions. The detection of outliers is tractable from a Bayesian approach. An experiment using fractionation of perceived brightness by continuous response adjustment is used as an illustrative example both for theory and for statistical analyses.
Estimation of multivariate polychoric and polyserial correlations with missing observations
Authors: Lee Sik‐Yum , Leung Kwan‐Moon
Published: August 2011

The main purpose of this paper is to investigate various approaches in analysing the multivariate polychoric and polyserial correlation model in the presence of incomplete data. For the general case with missing entries in both continuous and polytomous variables, a pseudo maximum likelihood method, and a partition pseudo maximum likelihood are developed. Iterative procedures based on the Fletcher–Powell algorithm and the Newton–Raphson algorithm are implemented to obtain various solutions. For the special case with missing entries only in the polytomous variables, a full maximum likelihood estimate is obtained with the help of an appropriate one–one onto transformation that significantly simplifies the computational burden. The analogous approaches as in the general case are also investigated. Finally, a simulation study is conducted to compare the performances of the various approaches.
A latent‐class regression approach for the analysis of recurrent choice data
Authors: Böckenholt Ulf
Published: August 2011

This paper introduces a mixture regression model for the analysis and interpretation of multivariate count data in a heterogeneous population. The model is derived by specifying a regression relationship at the individual level between the choice data and a set of concomitant variables. A latent class representation is introduced to describe variations in the regression weights among individuals and to obtain a representation of the aggregate choice behaviour. An easy‐to‐implement EM algorithm is presented for parameter estimation.
Lexicality and pronunciation in a simulated neural net
Authors: Phillips W. A. , Hay I. M. , Smith L. S.
Published: August 2011

Self‐supervised compressive neural nets can perform nonlinear multilevel latent structure analysis. They therefore have promise for cognitive theory. We study their use in the Seidenberg & McClelland (1989) model of reading. Analysis shows that self‐supervised compression in their model can make only a limited contribution to lexical decision, and simulation shows that it interferes with the associative mapping into phonology. Self‐supervised compression is therefore put to no good use in their model. This does not weaken the arguments for self‐supervised compression, however, and we suggest possible beneficial uses that merit further study.
Principal coordinates analysis with optimal transformation of the variables: Minimizing the sum of squares of the smallest eigenvalues
Authors: Meulman Jacqueline J.
Published: August 2011

Principal coordinates analysis (PCO) is a technique proposed by Gower (1966) to analyse a multivariate data matrix, representing the distances between the rows (the objects) by distances between object points in a low‐dimensional space, through an approximation using scalar products. For Euclidean distances, this paper generalizes the technique to a nonlinear variety, i.e. nonlinear transformations of the variables (the columns of the data matrix) are incorporated. These transformations are optimal according to the scalar product criterion that is minimized. This criterion can be re‐expressed in terms of the eigenvalues of the correlation matrix for the variables: nonlinear principal coordinates analysis then minimizes the sum of squares of a pre‐chosen number of small eigenvalues. The optimal nonlinear transformations are obtained by using iterative majorization.
A survey of theory and methods of invariant item ordering
Authors: Sijtsma Klaas , Junker Brian W.
Published: August 2011

In many testing situations, ordering the items by difficulty is helpful in analysing the testing data; examples include intelligence testing, analysis of differential item functioning, person‐fit analysis, and exploring hypotheses about the order in which cognitive operations are acquired by children. In each situation, interpretation and analysis are made easier if the items are ordered by difficulty in the same way for every individual taking the test, i.e. the item response functions do not cross. This is an invariant item ordering.

In this paper we review a class of non‐parametric unidimensional item response models in which the ordinal properties of items (and persons) can be studied, and survey both old and new methods for the investigation of invariant item ordering in empirical data sets. Our model formulation derives in particular fiom the work of Holland & Rosenbaum (1986), Junker (1993) and Mokken (1971). We survey methods based on the work of Mokken (1 97 I), Rosenbaum (1 987a, b), and Sijtsma & Meijer (1992), and we also discuss some new proposals for checking invariant item ordering. When violations are detected, these methods allow a rough assessment of where on the latent scale the item response functions cross.

We also study similarities and differences between these various methods and provide guidelines for their use. Finally, the methods are illustrated with data from a developmental psychology experiment in which the ability to draw inferences about transitive relations is explored.