The Analysis of Crop Variety Evaluation Data in Australia

The major aim of crop variety evaluation is to predict the future performance of varieties. This paper presents the routine statistical analysis of data from late-stage testing of crop varieties in Australia. It uses a two-stage approach for analysis. The data from individual trials from the current year are analysed using spatial techniques. The resultant table of variety-by-trial means is combined with tables from previous years to form the data for an overall mixed model analysis. Weights allow for the data being estimates with varying accuracy. In view of the predictive aim of the analysis, variety effects and interactions are regarded as random effects. Appropriate inferential tools have been developed to assist with interpretation of the results. Analyses must be conducted in a timely manner so that variety predictions can be published and disseminated to growers immediately after harvest each year. Factors which facilitate this include easy access to historic data and the use of specialist mixed model software.     

Can a voluntary web survey be useful beyond explorative research?

In this paper, we compare the estimates of earnings determinants based on the non-probabilistic WageIndicator web survey with those based on the widely used, representative EU Study of Income and Living Conditions survey. Using 10 years of Dutch data, we show that there exists an established segment of predominantly junior workers from which the respondents of the WageIndicator survey are disproportionally drawn. In consequence, the composition of WageIndicator sample tends to retain key characteristics over the years, even though it lacks a probabilistic sampling frame. We show that the estimates produced on the basis of an extended Mincerian earnings model using the two data sources are qualitatively similar. In line with much of the literature, however, the two sets of estimates do not pass the formal statistical test of equality. Nonetheless, when we examine only the subsample of junior workers, the statistical testing does not detect a statistically significant difference between the two datasets in many instances. To our knowledge, ours is the first paper showing such statistical evidence for comparability of a web survey based with a widely used representative data source.     

Factors affecting the structure of horticulture in the Vale of Evesham,U.K.: a behavioural interpretation

Horticulture in the Vale of Evesham is examined in relation to a set of grower and structural characteristics. Adopting a behavioural perspective, the relative importance of decision-making factors is assessed. Whilst physical factors dominate the ranking, socio-personal factors came first and third, with experience and such personal values as independence and doing the work you like influencing the decision behaviour of the horticulturists. The average ranking of economic factors reflects the problems facing the industry today. The importance of satisfaction is demonstrated and attention is drawn to the role of ‘opportunity cost’ and ‘social inertia’ in preventing a more rapid rate of decline.     

A simple measure of fertility control

We describe a simple measure of fertility control: the proportion of all births from the age-specific fertility schedule that occurs among women by age 35. This measure has broad applicability because it does not require information on marital fertility rates. When both the proportion of births by age 35 and the most commonly used measure of fertility control, m, are calculated for a population over time, they are correlated very highly. Because of increasing levels of nonmarital fertility in several developed countries, measures of fertility control that are based on marital fertility are less appropriate now than in the past.     

‘Pick me up and not a down down,up up’: how are the identities of people with aphasia represented in aphasia,stroke and disability websites?

Suddenly acquiring a permanent impairment means a person must learn to think differently (Frank, 1995), and he or she does so partly by telling stories. The most commonly told illness narratives are 'restitution' narratives. People with aphasia (a communication impairment commonly following stroke) surfed aphasia, stroke and disability websites, read the personal stories attached to them, and created their own narratives in response. Charitable and disability-related websites excluded people with aphasia through their tone, content and narrative 'voice.' Engagement with some websites was contingent on subscribing to a specific perspective on aphasia. Personal narratives attached to charitable websites were seen to reflect the organisational stance. In particular, idiosyncracies of aphasic language were often eliminated. When participants constructed their own web pages they replicated the stylistic traits that had previously been criticised. Identities are mercurial and difficult to pinpoint. Further work with people with aphasia using videoclips, soundclips and other non-text-based techniques to create illness narratives is planned.     

The individual welfare function : A comment

There appear to be a number of problems associated with the empirical measurement of the cardinal utility function discussed in the review by Kapteyn and Wansheek. The purpose of this comment is to explain these problems and to examine their implications.