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Inter-rater Reliability
In statistics, inter-rater reliability (also called by various similar names, such as inter-rater agreement, inter-rater concordance, inter-observer reliability, inter-coder reliability, and so on) is the degree of agreement among independent observers who rate, code, or assess the same phenomenon. Assessment tools that rely on ratings must exhibit good inter-rater reliability, otherwise they are not test validity, valid tests. There are a number of statistics that can be used to determine inter-rater reliability. Different statistics are appropriate for different types of measurement. Some options are joint-probability of agreement, such as Cohen's kappa, Scott's pi and Fleiss' kappa; or inter-rater correlation, concordance correlation coefficient, intra-class correlation, and Krippendorff's alpha. Concept There are several operational definitions of "inter-rater reliability," reflecting different viewpoints about what is a reliable agreement between raters. There are three oper ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Test Validity
Test validity is the extent to which a test (such as a chemical test, chemical, physical test, physical, or test (assessment), scholastic test) accuracy and precision, accurately measures what it is supposed to measurement, measure. In the fields of psychological testing and test (assessment), educational testing, "validity refers to the degree to which evidence and theory support the interpretations of test scores entailed by proposed uses of tests". Although classical models divided the concept into various "validities" (such as content validity, criterion validity, and construct validity), the currently dominant view is that validity is a single unitary construct. Validity is generally considered the most important issue in psychological and educational testing because it concerns the meaning placed on test results. Though many textbooks present validity as a static construct, various models of validity have evolved since the first published recommendations for constructing psy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spearman's Rank Correlation Coefficient
In statistics, Spearman's rank correlation coefficient or Spearman's ''ρ'' is a number ranging from -1 to 1 that indicates how strongly two sets of ranks are correlated. It could be used in a situation where one only has ranked data, such as a tally of gold, silver, and bronze medals. If a statistician wanted to know whether people who are high ranking in sprinting are also high ranking in long-distance running, they would use a Spearman rank correlation coefficient. The coefficient is named after Charles Spearman and often denoted by the Greek letter \rho (rho) or as r_s. It is a nonparametric measure of rank correlation ( statistical dependence between the rankings of two variables). It assesses how well the relationship between two variables can be described using a monotonic function. The Spearman correlation between two variables is equal to the Pearson correlation between the rank values of those two variables; while Pearson's correlation assesses linear relationshi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rating (pharmaceutical Industry)
Within the field of clinical trials, rating is the process by which a human evaluator subjectively judges the response of a patient to a medical treatment. The rating can include more than one treatment response. The assessor is normally an independent observer other than the patient, but the assessor can also be the patient (a patient-reported outcome). Furthermore, some clinical outcomes can only be assessed by the patient (a "private phenomenon"). Because the evaluation is subjective, this can result in both inter-rater or intra-rater reliability. When conducting clinical trials, ensuring rating consistency is important, but can prove to be quite difficult to obtain. Studies dealing with such indications as pain, mental disease A mental disorder, also referred to as a mental illness, a mental health condition, or a psychiatric disability, is a behavioral or mental pattern that causes significant distress or impairment of personal functioning. A mental disorder is . ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cronbach's Alpha
Cronbach's alpha (Cronbach's \alpha), also known as tau-equivalent reliability (\rho_T) or coefficient alpha (coefficient \alpha), is a reliability coefficient and a measure of the internal consistency of tests and measures. It was named after the American psychologist Lee Cronbach. Numerous studies warn against using Cronbach's alpha unconditionally. Statisticians regard reliability coefficients based on structural equation modeling (SEM) or generalizability theory as superior alternatives in many situations. History In his initial 1951 publication, Lee Cronbach described the coefficient as ''Coefficient'' ''alpha'' and included an additional derivation. ''Coefficient alpha'' had been used implicitly in previous studies, but his interpretation was thought to be more intuitively attractive relative to previous studies and it became quite popular. * In 1967, Melvin Novick and Charles Lewis proved that it was equal to reliability if the true scores of the compared tests ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Experimenter's Bias
Observer bias is one of the types of detection bias and is defined as any kind of systematic divergence from accurate facts during observation and the recording of data and information in studies. The definition can be further expanded upon to include the systematic difference between what is observed due to variation in observers, and what the true value is. Observer bias is the tendency of observers to not see what is there, but instead to see what they expect or want to see. This is a common occurrence in the everyday lives of many and is a significant problem that is sometimes encountered in scientific research and studies. Observation is critical to scientific research and activity, and as such, observer bias may be as well. When such biases exist, scientific studies can result in an over- or underestimation of what is true and accurate, which compromises the validity of the findings and results of the study, even if all other designs and procedures in the study were appropria ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computational Linguistics
Computational linguistics is an interdisciplinary field concerned with the computational modelling of natural language, as well as the study of appropriate computational approaches to linguistic questions. In general, computational linguistics draws upon linguistics, computer science, artificial intelligence, mathematics, logic, philosophy, cognitive science, cognitive psychology, psycholinguistics, anthropology and neuroscience, among others. Computational linguistics is closely related to mathematical linguistics. Origins The field overlapped with artificial intelligence since the efforts in the United States in the 1950s to use computers to automatically translate texts from foreign languages, particularly Russian scientific journals, into English. Since rule-based approaches were able to make arithmetic (systematic) calculations much faster and more accurately than humans, it was expected that lexicon, morphology, syntax and semantics can be learned using explicit rules, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Observational Studies
In fields such as epidemiology, social sciences, psychology and statistics, an observational study draws inferences from a sample to a population where the independent variable is not under the control of the researcher because of ethical concerns or logistical constraints. One common observational study is about the possible effect of a treatment on subjects, where the assignment of subjects into a treated group versus a control group is outside the control of the investigator. This is in contrast with experiments, such as randomized controlled trials, where each subject is randomly assigned to a treated group or a control group. Observational studies, for lacking an assignment mechanism, naturally present difficulties for inferential analysis. Motivation The independent variable may be beyond the control of the investigator for a variety of reasons: * A randomized experiment would violate ethical standards. Suppose one wanted to investigate the abortion – breast canc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Psychometrics
Psychometrics is a field of study within psychology concerned with the theory and technique of measurement. Psychometrics generally covers specialized fields within psychology and education devoted to testing, measurement, assessment, and related activities. Psychometrics is concerned with the objective measurement of latent constructs that cannot be directly observed. Examples of latent constructs include intelligence, introversion, mental disorders, and educational achievement. The levels of individuals on nonobservable latent variables are inferred through mathematical modeling based on what is observed from individuals' responses to items on tests and scales. Practitioners are described as psychometricians, although not all who engage in psychometric research go by this title. Psychometricians usually possess specific qualifications, such as degrees or certifications, and most are psychologists with advanced graduate training in psychometrics and measurement theory. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Survey Research
In research of human subjects, a survey is a list of questions aimed for extracting specific data from a particular group of people. Surveys may be conducted by phone, mail, via the internet, and also in person in public spaces. Surveys are used to gather or gain knowledge in fields such as social research and demography. Survey research is often used to assess thoughts, opinions and feelings. Surveys can be specific and limited, or they can have more global, widespread goals. Psychologists and sociologists often use surveys to analyze behavior, while it is also used to meet the more pragmatic needs of the media, such as, in evaluating political candidates, public health officials, professional organizations, and advertising and marketing directors. Survey research has also been employed in various medical and surgical fields to gather information about healthcare personnel’s practice patterns and professional attitudes toward various clinical problems and diseases. Healthcar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bland–Altman Plot
A Bland–Altman plot (difference plot) in analytical chemistry or biomedicine is a method of data plotting used in analyzing the agreement between two different assays. It is identical to a John Tukey, Tukey mean-difference plot, the name by which it is known in other fields, but was popularised in medical statistics by J. Martin Bland and Doug Altman, Douglas G. Altman. Construction Consider a sample consisting of n observations (for example, objects of unknown volume). Both assays (for example, different methods of volume measurement) are performed on each sample, resulting in 2n data points. Each of the n samples is then represented on the graph by assigning the mean of the two measurements as the x-value, and the difference between the two values as the y-value. The Cartesian coordinate system, Cartesian coordinates of a given sample S with values of S_1 and S_2 determined by the two assays is : S(x,y)=\left( \frac, S_1-S_2 \right). For comparing the dissimilarities ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
