Corrected confidence intervals for secondary parameters following sequential tests

Corrected confidence intervals are developed for the mean of the second component of a bivariate normal process when the first component is being monitored sequentially. This is accomplished by constructing a first approximation to a pivotal quantity, and then using very weak expansions to determine the correction terms. The asymptotic sampling distribution of the renormalised pivotal quantity is established in both the case where the covariance matrix is known and when it is unknown. The resulting approximations have a simple form and the results of a simulation study of two well-known sequential tests show that they are very accurate. The practical usefulness of the approach is illustrated by a real example of bivariate data. Detailed proofs of the main results are provided.Comment: Published at http://dx.doi.org/10.1214/074921706000000617 in the IMS Lecture Notes--Monograph Series (http://www.imstat.org/publications/lecnotes.htm) by the Institute of Mathematical Statistics (http://www.imstat.org

High-growth firms: introduction to the special section

High-growth firms (HGFs) have attracted considerable attention recently, as academics and policymakers have increasingly recognized the highly skewed nature of many metrics of firm performance. A small number of HGFs drives a disproportionately large amount of job creation, while the average firm has a limited impact on the economy. This article explores the reasons for this increased interest, summarizes the existing literature, and highlights the methodological considerations that constrain and bias research. This special section draws attention to the importance of HGFs for future industrial performance, explores their unusual growth trajectories and strategies, and highlights the lack of persistence of high growth. Consequently, while HGFs are important for understanding the economy and developing public policy, they are unlikely to be useful vehicles for public policy given the difficulties involved in predicting which firms will grow, the lack of persistence in high growth levels, and the complex and often indirect relationship between firm capability, high growth, and macro-economic performance

Death is not a success: reflections on business exit

This article is a critical evaluation of claims that business exits should not be seen as failures, on the grounds that may constitute voluntary liquidation, or because they are learning opportunities. This can be seen as further evidence of bias affecting entrepreneurship research, where failures are repackaged as successes. This article reiterates that the majority of business exits are unsuccessful. Drawing on ideas from the organisational life course, it is suggested that business ‘death’ is a suitable term for describing business closure. Even cases of voluntary ‘harvest liquidation’ such as retirement can be meaningfully described as business deaths

Disclosing terminal diagnosis to children and their families: palliative professionals' communication barriers

Few studies have fully explored the problem of communication barriers in pediatric palliative care, particularly the detrimental effects of poor interaction between staff and families on children's health and well-being. A literature review was undertaken to expand the current body of knowledge about staff to patient communications. Articles meeting the inclusion criteria (N = 15) were systematically read and summarized using a data extraction sheet. A narrative synthesis identified 5 overarching themes as barriers to communication. Improvements in staff education and individualized palliative care plans for children and their families may help to overcome communication barriers

Pattern languages in HCI: A critical review

This article presents a critical review of patterns and pattern languages in human-computer interaction (HCI). In recent years, patterns and pattern languages have received considerable attention in HCI for their potential as a means for developing and communicating information and knowledge to support good design. This review examines the background to patterns and pattern languages in HCI, and seeks to locate pattern languages in relation to other approaches to interaction design. The review explores four key issues: What is a pattern? What is a pattern language? How are patterns and pattern languages used? and How are values reflected in the pattern-based approach to design? Following on from the review, a future research agenda is proposed for patterns and pattern languages in HCI

An Exploration of the Data Collection Methods Utilised with Children, Teenagers and Young People (CTYPs)

Background: The impact of cancer upon children, teenagers and young people can be profound. Research has been undertaken to explore the impacts upon children, teenagers and young people with cancer, but little is known about how researchers can ‘best’ engage with this group to explore their experiences. This review paper provides an overview of the utility of data collection methods employed when undertaking research with children, teenagers and young people. A systematic review of relevant databases was undertaken utilising the search terms ‘young people’, ‘young adult’, ‘adolescent’ and ‘data collection methods’. The full-text of the papers that were deemed eligible from the title and abstract were accessed and following discussion within the research team, thirty papers were included. Findings: Due to the heterogeneity in terms of the scope of the papers identified the following data collections methods were included in the results section. Three of the papers identified provided an overview of data collection methods utilised with this population and the remaining twenty seven papers covered the following data collection methods: Digital technologies; art based research; comparing the use of ‘paper and pencil’ research with web-based technologies, the use of games; the use of a specific communication tool; questionnaires and interviews; focus groups and telephone interviews/questionnaires. The strengths and limitations of the range of data collection methods included are discussed drawing upon such issues as of the appropriateness of particular methods for particular age groups, or the most appropriate method to employ when exploring a particularly sensitive topic area. Conclusions: There are a number of data collection methods utilised to undertaken research with children, teenagers and young adults. This review provides a summary of the current available evidence and an overview of the strengths and limitations of data collection methods employed

New venture survival and growth: Does the fog lift?

Does our ability to predict the performance of new ventures improve in the years after start-up? We investigate the growth and survival of 6247 new ventures that are tracked using the customer records at Barclays Bank. We put forward Gambler’s Ruin as a simple theory for understanding new venture growth and survival. Gambler’s Ruin predicts that the R2 remains low for growth rate regressions, but that the R2 increases in the years since start-up for survival regressions. The Nagelkerke R2 obtained from growth rate regressions decreases significantly in the years after start-up, which suggests that the fog gets thicker with respect to growth. When we focus only on firms surviving until the end of the period, however, there is no visible change in the R2 over time. In contrast, the Nagelkerke R2 of survival regressions increases in the years after start-up. Interestingly, a blip in year 5 suggests that macro-economic factors may have a strong effect on the amount of ‘fog’

Business experience and start-up size: buying more lottery tickets next time around?

This paper explores the determinants of start-up size by focusing on a cohort of 6247 businesses that started trading in 2004, using a unique dataset on customer records at Barclays Bank. Quantile regressions show that prior business experience is significantly related with start-up size, as are a number of other variables such as age, education and bank account activity. Quantile treatment effects (QTE) estimates show similar results, with the effect of business experience on (log) start-up size being roughly constant across the quantiles. Prior personal business experience leads to an increase in expected start-up size of about 50%. Instrumental variable QTE estimates are even higher, although there are concerns about the validity of the instrument