We study two notions of definability for classes of relational structures based on modal extensions of Łukasiewicz finitely-valued logics. The main results of the paper are the equivalent of the Goldblatt Thomason theorem for these notions of definability.

basic requirement of many studies is the necessity of classifying data. Clustering is a proposed method for summarizing networks. Clustering methods can be divided into two categories named model-based approaches and algorithmic approaches. Since the most of clustering methods depend on their input parameters, it is important to evaluate the result of a clustering algorithm with its' different ...

BACKGROUND Validity evidence based on response processes was first introduced explicitly as a source of validity evidence in the latest edition of Standards for Educational and Psychological Testing. In this paper, we present the theory, the relationship with other sources of validity evidence, and the methods available for validation studies aimed at obtaining validity evidence about response ...

Games are seen as attractive potential learning tools because of their ability to engage players and immerse them in situations that invite application of content and skills. However, it is not always clear whether educational games encourage players to utilize particular cognitive processes, access appropriate prior knowledge concepts, and/or apply given procedural skills as intended. Research...

BACKGROUND Large-scale educational assessments in the U.S. are used as policy tools for improving instruction and evaluating educational programs and the effectiveness of educators. Because of the high-stakes nature of their use, it is imperative that validity evidence based on testing consequences is obtained to support their multiple purposes. METHOD A comprehensive review of the literature...

Much of the methodological discussion around experiments in economics and other social sciences is framed in terms of the notions of internal and external validity. The standard view is that internal validity and external validity stand in a relationship best described as a trade-off. However, it is also commonly held that internal validity is a prerequisite to external validity. This article a...

CONTEXT The transition to retirement has been recognized as a turning point in determining physical activity and may present a critical "window" for promoting physical activity. This systematic review examined changes in physical activity across the retirement transition, whether these changes vary by SES, and what is known about predictors of these changes. EVIDENCE ACQUISITION Peer-reviewed...

Randomized controlled trials (RCTs) are routinely used in medicine and are becoming more popular in economics. Data from RCTs are used to learn about treatment effects of interest. This paper studies what one can learn about the average treatment response (ATR) and average treatment effect (ATE) from RCT data under various assumptions and compares that to using observational data. We find that ...

Validity is an enduring theme in the information systems (IS) domain. However, because much of that discussion draws, at least nominally, on an Empiricist orientation, formulating issues of validity in a way that is pertinent to a practice-oriented discipline has been difficult. This is particularly true for external validity, which refers to the applicability, or relevance, of research to phen...

OBJECTIVE The Centers for Disease Control and Prevention's National Public Health Performance Standards Program (NPHPSP) has developed instruments to measure the performance of local and state public health departments on the 10 "Essential Services of Public Health," which have been tested in several states. This article is a report of the evaluation of the content and criterion validity of the...