Where we stand today in the practice of evaluation: Some reflections

It is a great pleasure and privilege to be here in The Hague this morning to help celebrate what we hope will be a first historic meeting of the European Evaluation Society. It’s a happy day, not only because of the international character of this group and its impressive collective credentials, but also because this conference fits so well into the generally high hopes and expectations that we have for evaluation today. Eleanor Chelimsky is GAO’s Assistant Comptroller General for Program Evaluation. Since 1980, she has directed GAO’s Program Evaluation and Methodology Division. Chelimsky is a member of the advisory boards for the University of Chicago’s School of Social Service Administration and for Camegie-Mellon’s John Heinz School of Public Policy. She is also a member of the editonal review board for the Sage Research Series in Evaluation and serves on the editorial boards of two joumals:Policy Studies Review andPolicy Studies Review Annual.     

Mental age and cognitive stage in young handicapped and at-risk children

This research addressed the question of whether stage-related patterns of early cognitive development, reported for normally developing children in the first two and a half years of life, may also characterize the development of at-risk and handicapped children when mental age rather than chronological age is used to organize the data. Performance on a psychometric infant test and two neo-Piagetian-based stage measures was assessed for 95 at-risk and handicapped children. Mental age predicted cognitive level of performance for levels 1 to 3, representing the first year and a half of development, but did not predict the highest level, symbolic functioning. In addition, transition points between levels were observed at mental ages similar to the chronological ages when these transitions have been reported for normally developing infants, for all but the last level. The significance of the correspondence between the psychometric measure and the stage measures is discussed and several alternatives for the breakdown at the highest level are considered.     

Measures of play behavior: The influence of sex-role stereotyped children's books

Preschool children significantly more often chose a sex-stereotypic toy following exposure to a sex-stereotypic children's book. Conversely, boys and girls exposed to a nonstereotypic book significantly more often selected a nonstereotypic toy. Boys and girls individually played with stereotypic male, female, and neutral toys; each child was then read a sex-role stereotypic or nonstereotypic picture book; another play session followed. Measures of visual regard and manipulation were applied to the observed play behavior of 32 preschool children to determine the significance of the findings.     

Family resemblances: Studies in the internal structure of categories

Six experiments explored the hypothesis that the members of categories which are considered most prototypical are those with most attributes in common with other members of the category and least attributes in common with other categories. In probabilistic terms, the hypothesis is that prototypicality is a function of the total cue validity of the attributes of items. In Experiments 1 and 3, subjects listed attributes for members of semantic categories which had been previously rated for degree of prototypicality. High positive correlations were obtained between those ratings and the extent of distribution of an item's attributes among the other items of the category. In Experiments 2 and 4, subjects listed superordinates of category members and listed attributes of members of contrasting categories. Negative correlations were obtained between prototypicality and superordinates other than the category in question and between prototypicality and an item's possession of attributes possessed by members of contrasting categories. Experiments 5 and 6 used artificial categories and showed that family resemblance within categories and lack of overlap of elements with contrasting categories were correlated with ease of learning, reaction time in identifying an item after learning, and rating of prototypicality of an item. It is argued that family resemblance offers an alternative to criterial features in defining categories.     

Basic objects in natural categories

Categorizations which humans make of the concrete world are not arbitrary but highly determined. In taxonomies of concrete objects, there is one level of abstraction at which the most basic category cuts are made. Basic categories are those which carry the most information, possess the highest category cue validity, and are, thus, the most differentiated from one another. The four experiments of Part I define basic objects by demonstrating that in taxonomies of common concrete nouns in English based on class inclusion, basic objects are the most inclusive categories whose members: (a) possess significant numbers of attributes in common, (b) have motor programs which are similar to one another, (c) have similar shapes, and (d) can be identified from averaged shapes of members of the class. The eight experiments of Part II explore implications of the structure of categories. Basic objects are shown to be the most inclusive categories for which a concrete image of the category as a whole can be formed, to be the first categorizations made during perception of the environment, to be the earliest categories sorted and earliest named by children, and to be the categories most codable, most coded, and most necessary in language.     

A developmental study of visual search behavior

Children in second, fourth and sixth grades and college sophomores were compared on a visual search and scanning task under three experimental conditions. In Condition I, a single target letter was sought in a list of letters of low visual confusability. In Condition II, two target letters were sought but only one appeared in a given list. In Condition III, a single target letter was sought in a list of letters of high confusability. Search time decreased with age in all three tasks. Searching for two targets was no harder than searching for one. A highly confusable visual context increased search time at all age levels.     

Compound-stimulus information processing by 3-month-old infants

According to Cohen's (1973) component-compound developmental hypothesis, before 20 weeks of age, infants do not process compound-stimulus information when presented with simple colored forms. This hypothesis was examined in the present study. Eighty 3-month-old infants were presented with novel and familiar simple colored forms (e.g., red square vs. green square). Conditions were controlled so that novelty discriminations based on component- or compound-stimulus information could be separated. Contrary to the component-compound developmental hypothesis, the results indicate that by 12 weeks of age infants encode compound-stimulus information when presented with simple colored forms. These results are discussed in terms of the property-set model of stimulus recognition (Hayes-Roth & Hayes-Roth, 1977).