Local Standards for Sample Size at CHI

We describe the primary ways researchers can determine the size of a sample of research participants, present the benefits and drawbacks of each of those methods, and focus on improving one method that could be useful to the CHI community: local standards. To determine local standards for sample size within the CHI community, we conducted an analysis of all manuscripts published at CHI2014. We find that sample size for manuscripts published at CHI ranges from 1 -- 916,000 and the most common sample size is 12. We also find that sample size differs based on factors such as study setting and type of methodology employed. The outcome of this paper is an overview of the various ways sample size may be determined and an analysis of local standards for sample size within the CHI community. These contributions may be useful to researchers planning studies and reviewers evaluating the validity of results

Worse Than Spam: Issues In Sampling Software Developers

Background: Reaching out to professional software developers is a crucial part of empirical software engineering research. One important method to investigate the state of practice is survey research. As drawing a random sample of professional software developers for a survey is rarely possible, researchers rely on various sampling strategies. Objective: In this paper, we report on our experience with different sampling strategies we employed, highlight ethical issues, and motivate the need to maintain a collection of key demographics about software developers to ease the assessment of the external validity of studies. Method: Our report is based on data from two studies we conducted in the past. Results: Contacting developers over public media proved to be the most effective and efficient sampling strategy. However, we not only describe the perspective of researchers who are interested in reaching goals like a large number of participants or a high response rate, but we also shed light onto ethical implications of different sampling strategies. We present one specific ethical guideline and point to debates in other research communities to start a discussion in the software engineering research community about which sampling strategies should be considered ethical.Comment: 6 pages, 2 figures, Proceedings of the 2016 ACM/IEEE International Symposium on Empirical Software Engineering and Measurement (ESEM 2016), ACM, 201

Connecting British Columbia (Canada) school libraries and student achievement: A comparison of higher and lower performing schools with similar overall funding

Research over time has established associations between components of the school library and student achievement. This study was designed to investigate these associations in schools in British Columbia (Canada) where the government provides equitable funding of public schools while allowing individual school districts and schools to determine individual funding priorities. Findings replicated what numerous previous studies have shown: higher student standardized test scores were associated with a school library that is more accessible, better funded, professionally staffed, managed, stocked, integrated and used. Findings moreover pointed to higher student achievement in those schools where greater resources, from the same limited allocation were assigned to school libraries. Results of this study are of practical interest to policy makers, school and library administrators, and educators with a vested interest in student achievement and the future of school libraries. Reprinted by permission of the publisher

Analyzing urban poverty: a summary of methods and approached

In recent years an extensive body of literature has emerged on the definition, measurement and analysis of poverty. Much of this literature focuses on analyzing poverty at the national level, or spatial disaggregation by general categories of urban or rural areas with adjustments made for regional price differentials. Yet for an individual city attempting to tackle the problems of urban poverty, this level of aggregation is not sufficient for answering specific questions such as where the poor are located in the city, whether there are differences between poor areas, if access to services varies by subgroup, whether specific programs are reaching the poorest, and how to design effective poverty reduction programs and policies. Answering these questions is critical, particularly for large, sprawling cities with highly diverse populations and growing problems of urban poverty. Understanding urban poverty presents a set of issues distinct from general poverty analysis and thus may require additional tools and techniques. This paper summarizes the main issues in conducting urban poverty analysis, with a focus on presenting a sample of case studies from urban areas that were implemented by a number of different agencies using a range of analytical approaches for studying urban poverty. Specific conclusions regarding design and analysis, data, timing, cost, and implementation issues are discussed.Public Health Promotion,Poverty Reduction Strategies,Health Economics&Finance,Poverty Monitoring&Analysis,Health Monitoring&Evaluation,Urban Partnerships&Poverty,Poverty Reduction Strategies,Health Economics&Finance,Poverty Assessment,City Development Strategies

Green noise or green value? Measuring the price effects of environmental certification in commercial buildings

This paper investigates the price effects of environmental certification on commercial real estate assets. It is argued that there are likely to be three main drivers of price differences between certified and non-certified buildings. First, certified buildings offer a bundle of benefits to occupiers relating to business productivity, image and occupancy costs. Second, due to these occupier benefits, certified buildings can result in higher rents and lower holding costs for investors. Third, certified buildings may require a lower risk premium. Drawing upon the CoStar database of US commercial real estate assets, hedonic regression analysis is used to measure the effect of certification on both rent and price. We first estimate the rental regression for a sample of 110 LEED and 433 Energy Star as well as several thousand benchmark buildings to compare the sample to. The results suggest that, compared to buildings in the same metropolitan region, certified buildings have a rental premium and that the more highly rated that buildings are in terms of their environmental impact, the greater the rental premium. Furthermore, based on a sample of transaction prices for 292 Energy Star and 30 LEED-certified buildings, we find price premia of 10% and 31% respectively compared to non-certified buildings in the same metropolitan are

Assessment of the dimensionality of the Wijma delivery expectancy/experience questionnaire using factor analysis and Rasch analysis

Background: Fear of childbirth has negative consequences for a woman's physical and emotional wellbeing. The most commonly used measurement tool for childbirth fear is the Wijma Delivery Expectancy Questionnaire (WDEQ-A). Although originally conceptualized as unidimensional, subsequent investigations have suggested it is multidimensional. This study aimed to undertake a detailed psychometric assessment of the WDEQ-A; exploring the dimensionality and identifying possible subscales that may have clinical and research utility. Methods: WDEQ-A was administered to a sample of 1410 Australian women in mid-pregnancy. The dimensionality of WDEQ-A was explored using exploratory (EFA) and confirmatory factor analysis (CFA), and Rasch analysis. Results: EFA identified a four factor solution. CFA failed to support the unidimensional structure of the original WDEQ-A, but confirmed the four factor solution identified by EFA. Rasch analysis was used to refine the four subscales (Negative emotions: five items; Lack of positive emotions: five items; Social isolation: four items; Moment of birth: three items). Each WDEQ-A Revised subscale showed good fit to the Rasch model and adequate internal consistency reliability. The correlation between Negative emotions and Lack of positive emotions was strong, however Moment of birth and Social isolation showed much lower intercorrelations, suggesting they should not be added to create a total score. Conclusion: This study supports the findings of other investigations that suggest the WDEQ-A is multidimensional and should not be used in its original form. The WDEQ-A Revised may provide researchers with a more refined, psychometrically sound tool to explore the differential impact of aspects of childbirth fear.Full Tex