Maximum versus Meaningful Discrimination in Scale Response: Implications for Validity of Measurement of Consumer Perceptions about Products

This paper argues for the use of the number of response categories that are meaningful to respondents as a criterion in designing attribute rating scales in marketing in contrast to a focus in past research on using scales to maximize the discrimination elicited from respondents. Whereas scales eliciting a maximum level of discrimination may be more reliable than scales eliciting a meaningful level of discrimination, the latter are argued to be more valid in measuring sameness and difference between brands that are meaningful to respondents. Specifically, a distinction is drawn in this paper between the maximum number of categories that consumers can discriminate between and the number of categories that are meaningful to them. The meaningful number of categories refers to the number of categories that individuals typically use in thinking about an attribute in such situations as making a choice or judgment. Thus, the unique perspective of consumer behavior with its central focus on phenomena such as product judgment and choice is incorporated into the measurement of consumers\u27 perceptions about attributes. Several studies were conducted to test hypotheses generated on the basis of the notion of the meaningful number of categories. The first study used an open-ended method (i.e., a sorting task) to measure the number of categories that are meaningful to consumers for specific attributes. Using the results of the first study as a basis, two studies demonstrated the effect of the meaningful number of categories for an attribute on scale response such that fewer scale points were used to rate products on attributes with fewer meaningful numbers of categories. Another study showed that a scale with the meaningful number of categories might be more accurate than other scales in predicting sameness and difference between brands that are meaningful to consumers. The significance of using scales with a meaningful number of categories is in validly measuring differences between products that are meaningful to consumers

Why does the Engel method work? Food demand, economies of size and household survey methods

Estimates of household size economies are needed for the analysis of poverty and inequality. This paper shows that Engel estimates of size economies are large when household expenditures are obtained by respondent recall but small when expenditures are obtained by daily recording in diaries. Expenditure estimates from recall surveys appear to have measurement errors correlated with household size. As well as demonstrating the fragility of Engel estimates of size economies, these results help resolve a puzzle raised by Deaton and Paxson (1998) about differences between rich and poor countries in the effect of household size on food demand

A Comparison of Recall and Diary Food Expenditure Data

Recall food expenditure data, which is the basis of a great deal of empirical work, is believed to suffer from considerable measurement error. Diary records are believed to be more accurate. We study an unusual data set that collects recall and diary data from the same households and so allows a direct comparison of the two methods of data collection. The diary data imply measurement errors in recall food expenditure data that are substantial, and which do not have the properties of classical measurement error. However, we also present evidence that the diary measures are themselves imperfect

The accuracy of presidential preference primary polls / 196

Includes bibliographical references

Minimax strategies in survey sampling

The risk of a sampling strategy is a function on the parameter space, which is the set of all vectors composed of possible values of the variable of interest. It seems natural to ask for a minimax strategy, minimizing the maximal risk. So far answers have been provided for completely symmetric parameter spaces. Results available for more general spaces refer to sample size 1 or to large sample sizes allowing for asymptotic approximation. In the present paper we consider arbitrary sample sizes, derive a lower bound for the maximal risk under very weak conditions and obtain minimax strategies for a large class of parameter spaces. Our results do not apply to parameter spaces with strong deviations from symmetry. For such spaces a minimax strategy will prescribe to consider only a small number of samples and takes a non-random and purposive character

Disparate Rates of Molecular Evolution in Cospeciating Hosts and Parasites

DNA sequences for the gene encoding mitochondrial cytochrome oxidase I in a group of rodents (pocket gophers) and their ectoparasites (chewing lice) provide evidence for cospeciation and reveal different rates of molecular evolution in the hosts and their parasites. The overall rate of nucleotide substitution (both silent and replacement changes) is approximately three times higher in lice, and the rate of synonymous substitution (based on analysis of fourfold degenerate sites) is approximately an order of magnitude greater in lice. The difference in synonymous substitution rate between lice and gophers correlates with a difference of similar magnitude in generation times

Hmong Adults Self-Rated Oral Health: A Pilot Study

Since 1975, the Hmong refugee population in the U.S. has increased over 200%. However, little is known about their dental needs or self-rated oral health (SROH). The study aims were to: (1) describe the SROH, self-rated general health (SRGH), and use of dental/physician services; and (2) identify the factors associated with SROH among Hmong adults. A cross-sectional study design with locating sampling methodology was used. Oral health questionnaire was administered to assess SROH and SRGH, past dental and physician visits, and language preference. One hundred twenty adults aged 18–50+ were recruited and 118 had useable information. Of these, 49% rated their oral health as poor/fair and 30% rated their general health as poor/fair. Thirty-nine percent reported that they did not have a regular source of dental care, 46% rated their access to dental care as poor/fair, 43% visited a dentist and 66% visited a physician within the past 12 months. Bivariate analyses demonstrated that access to dental care, past dental visits, age and SRGH were significantly associated with SROH (P \u3c 0.05). Multivariate analyses demonstrated a strong association between access to dental care and good/excellent SROH. About half of Hmong adults rated their oral health and access to dental care as poor. Dental insurance, access to dental care, past preventive dental/physician visits and SRGH were associated with SROH

On transition bias in mitochondrial genes of pocket gophers

Abstract. The relative contribution of mutation and purifying selection to transition bias has not been quantitatively assessed in mitochondrial protein genes. The observed transition/transversion (s/v) ratio is ( s P s )/( v P v ), where s and v denote mutation rate of transitions and transversions, respectively, and P s and P v denote fixation probabilities of transitions and transversions, respectively. Because selection against synonymous transitions can be assumed to be roughly equal to that against synonymous transversions, P s /P v ≈ 1 at fourfold degenerate sites, so that the s/v ratio at fourfold degenerate sites is approximately s / v , which is a measure of mutational contribution to transition bias. Similarly, the s/v ratio at nondegenerate sites is also an estimate of s / v if we assume that selection against nonsynonymous transitions is roughly equal to that against nonsynonymous transversions. In two mitochondrial genes, cytochrome oxidase subunit I (COI) and cytochrome b (cyt-b) in pocket gophers, the s/v ratio is about two at nondegenerate and fourfold degenerate sites for both the COI and the cyt-b genes. This implies that mutation contribution to transition bias is relatively small. In contrast, the s/v ratio is much greater at twofold degenerate sites, being 48 for COI and 40 for cyt-b. Given that the s / v ratio is about 2, the P s /P v ratio at twofold degenerate sites must be on the order of 20 or greater. This suggests a great effect of purifying selection on transition bias in mitochondrial protein genes because transitions are synonymous and transversions are nonsynonymous at twofold degenerate sites in mammalian mitochondrial genes. We also found that nonsynonymous mutations at twofold degenerate sites are more neutral than nonsynonymous mutations at nondegenerate sites, and that the COI gene is subject to stronger purifying selection than is the cyt-b gene. A model is presented to integrate the effect of purifying selection, codon bias, DNA repair and GC content on s/v ratio of protein-coding genes