An analysis of consumer panel data

In terms of collecting comprehensive panel expenditure data, there are trade-offs to be made in terms of the demands imposed on respondents and the level of detail and spending coverage collected. Existing comprehensive spending data tends to be cross-sectional whilst panel studies include only limited expenditure questions that record spending only as broad aggregates. More recently, economists have begun to use spending information collected by market research companies that records very detailed spending down to the barcode level from a panel of households, usually recorded by in-home barcode scanners, which may provide considerable advantages over existing data more commonly used in social sciences. However, there has not been a comprehensive assessment of the strengths and weaknesses of this kind of data collection method and the potential implications of survey mode on the recorded data. This paper seeks to address this, by an in-depth examination of scanner data from one company, Taylor Nelson Sofres (TNS), on grocery purchases over a five-year period. We assess how far the ongoing demands of participation inherent in this kind of survey lead to 'fatigue' in respondents' recording of their spending and compare the demographic representativeness of the data to the well-established Expenditure and Food Survey (EFS), constructing weights for the TNS that account for observed demographic differences. We also look at demographic transitions, comparing the panel aspect of the TNS to the British Household Panel Study (BHPS). We examine in detail the expenditure data in the TNS and EFS surveys and discuss the implications of this method of data collection for survey attrition. Broadly, we suggest that problems of fatigue and attrition may not be so severe as may be expected, though there are some differences in expenditure levels (and to some extent patterns of spending) that cannot be attributed to demographic or time differences in the two surveys alone and may be suggestive of survey mode effects. Demographic transitions appear to occur less frequently than we might expect which may limit the usefulness of the panel aspect of the data for some applications

Consumption trends in the UK, 1975-99

How and why has the way in which the average British family spends its money changed over the past 25 years? Those are the key questions examined in this report, using data from the UK FES between 1975 and 1999. It looks not only at broad changes in total spending, but also at how the division of expenditure between basics and non-basics and between durable goods, non-durable goods and services has altered over time

London's congestion charge

On 17 February 2003, one of the world's largest and most ambitious plans to tackle urban congestion began, with the introduction of a congestion charge for central London. It is hoped that this £5 daily charge for many vehicles entering the Inner Ring Road charging zone will significantly reduce the level of congestion faced by those travelling into and out of central London both by private and by public transport. In 2001, almost 1.1 million people entered central London during the morning peak hours of 7.00a.m.-10.00a.m.,1 of whom around 150,000 (13.7%) used private transport. Whilst the total number of people entering during the morning rush hour has scarcely changed since 1991, there has been a small shift towards public transport: in 1991, 16.8% of people used private transport. Nevertheless, average traffic speeds in central London have fallen slightly over the last decade, with the average morning peak-period traffic speed for 2000-03 just 9.9 mph, compared with a peak of 14.2 mph in 1974-76. During the evening rush hour, average speeds are even slower, at just 9.6 mph. In evidence to the House of Commons Transport Committee,3 David Begg of the Commission for Integrated Transport argues that around 40% of the total national level of congestion occurs in Greater London. Transport for London suggests that "there are now no longer any "peaks" or "off-peaks" of traffic volume between 7am - 6.30pm" and states that there are now on average three minutes of delay for every mile that a vehicle travels inside the charging zone. This Briefing Note aims to provide a guide to the workings of the London congestion charge. We begin in Section 2 by describing the economic case for congestion charging, showing why congestion can be thought of as an urban example of the well-known overuse of common resources to which there is free access (the so-called "tragedy of the commons"). In Section 3, we move on to look at the details of the proposed charge for London, examining how it fits in with the economic framework we develop and discussing some of the work that has already been carried out to try to predict the likely effects of the charge. Section 4 looks briefly at the issue of what may happen with the projected net revenues from the charge, which are legally bound for the first 10 years to be spent on transport within Greater London. In Section 5, we discuss some of the empirical evidence regarding transport in London and present evidence on the potential distributional effects of the congestion charge, since one of the oft-cited criticisms of charging is that it will impact upon the poorest most severely. Section 6 goes on to look at the experience of congestion charging elsewhere around the world

Encountering soviet geography: oral histories of British geographical studies of the USSR and Eastern Europe 1945-1991

This paper considers the history of British geographical studies of the USSR and Eastern Europe 1945-1991, presenting material from a research project which has included thirty-two oral history interviews. Oral history is an especially fruitful research methodology in this context due to the distinct issues of formality and informality involved in researching the Soviet bloc. After discussing the nature of the subdiscipline and the Cold War context, including the role of the British state in shaping the field, the paper considers the role of formal academic meetings and exchanges, and the place of unofficial spaces of encounter in the formation of an intellectual culture. The paper concludes by reflecting on the merits of oral history in studies of the production of geographical knowledge

The expenditure experience of older households

This commentary examines detailed trends in expenditure patterns between 1995 and 2007, with a particular focus on the pensioner population. Pensioners are not a homogeneous group, but differ widely in both their levels and patterns of spending, and so we look not just at pensioners as a whole but also at pensioners according to age, income, household composition and so on. Spending may tell us something about household welfare that other, often-used measures like incomes do not. In particular, it may be that spending is informative about long-run well-being whereas income is more about current, short-run living standards. Using data from the Family Expenditure Survey/Expenditure and Food Survey, an annual, cross-sectional study of the spending patterns of 6,000-7,000 households, we look in depth at changes in the level of real expenditures and how spending patterns have changed over time. Then, using data from two waves of the English Longitudinal Study of Ageing, we examine household fuel expenditures in detail. Fuel is clearly of great current policy concern given recent large increases in the price of domestic fuel that may impact particularly severely on poorer and older households

The inflation experience of older households

Recent increases in inflation have been accompanied by concerns over the extent to which official figures match the 'true' household experience of inflation. Rapid increases in the prices of household fuel, petrol and diesel and, more recently, of food have brought considerable attention to the fact that inflation will be different for different households according to their expenditure patterns. Any measure of inflation, such as the Retail Prices Index (RPI) or Consumer Prices Index (CPI), is necessarily only an average of the experience of different households and may not be especially representative of what is happening for any household in particular. Using data from the Expenditure and Food Survey, this Commentary looks at the inflation experience (based on the RPI) for different groups of households, examining how the average inflation rate they face has varied over time and making comparisons across the groups, focusing in particular on pensioner households

Study of ceramic products and processing techniques in space

An analysis of the solidification kinetics of beta alumina in a zero-gravity environment was carried out, using computer-simulation techniques, in order to assess the feasibility of producing high-quality single crystals of this material in space. The two coupled transport processes included were movement of the solid-liquid interface and diffusion of sodium atoms in the melt. Results of the simulation indicate that appreciable crystal-growth rates can be attained in space. Considerations were also made of the advantages offered by high-quality single crystals of beta alumina for use as a solid electrolyte; these clearly indicate that space-grown materials are superior in many respects to analogous terrestrially-grown crystals. Likewise, economic considerations, based on the rapidly expanding technological applications for beta alumina and related fast ionic conductors, reveal that the many superior qualities of space-grown material justify the added expense and experimental detail associated with space processing

Efficient I/O for Computational Grid Applications

High-performance computing increasingly occurs on computational grids composed of heterogeneous and geographically distributed systems of computers, networks, and storage devices that collectively act as a single virtual computer. A key challenge in this environment is to provide efficient access to data distributed across remote data servers. This dissertation explores some of the issues associated with I/O for wide-area distributed computing and describes an I/O system, called Armada, with the following features: a framework to allow application and dataset providers to flexibly compose graphs of processing modules that describe the distribution, application interfaces, and processing required of the dataset before or after computation; an algorithm to restructure application graphs to increase parallelism and to improve network performance in a wide-area network; and a hierarchical graph-partitioning scheme that deploys components of the application graph in a way that is both beneficial to the application and sensitive to the administrative policies of the different administrative domains. Experiments show that applications using Armada perform well in both low- and high-bandwidth environments, and that our approach does an exceptional job of hiding the network latency inherent in grid computing

Investigation of immiscible systems and potential applications

The droplet coalescence kinetics at 0 g and 1 g were considered for two systems which contained liquid droplets in a host liquid. One of these (Al-In) typified a system containing a liquid phase miscibility gap and the order (oil-water) a mixture of two essentially insoluble liquids. A number of coalescence mechanisms potentially prominent at low g in this system were analyzed and explanations are presented for the observed unusual stability of the emulsion. Ground base experiments were conducted on the coalescence of In droplets in and Al-In alloy during cooling through the miscibility gap at different cooling rates. These were in qualitative agreement with the computer simulation. Potential applications for systems with liquid phase miscibility gaps were explored. Possibilities included superconductors, electrical contact materials, superplastic materials, catalysts, magnetic materials, and others. The role of space processing in their production was also analyzed