Plaid designs for the evaluation of training for medical practitioners

The training of medical practitioners to improve the practitioner/patient relationship may be difficult, as limitations often exist on the choice of patients included in the study. A specific study of this type of training is given. It is proposed that a simple modification and generalization of Yates' plaid-square designs be used. It is shown that a replicated plaid-design incorporates as a special case the criss-cross or strip-plot design. The usefulness of these designs in studies of the training of medical practitioners is illustrated. The basic characteristics of their analysis are outlined.     

The impact of the social environment on nursing home residents

This study contrasted the experienced quality of life of residents living on one of two nursing home units: a unit for those considered socially intact and a unit combining residents who had moderately impaired cognition or physical function with those requiring skilled nursing or therapy. Qualitative interviews were held with residents of both units. The findings indicate that the social environment of each of the units played a fundamental role in the residents' quality of life. The social environment affected the residents' conceptions of self, their interactions with other residents and their interactions with the nursing staff. The article suggests the processes behind the social environment of each floor that may have resulted in different perceptions of the quality of life.     

The robustness and optimality of response surface designs

Recent work on extended optimality criteria for robust designs is applied to response surface problems. Methods of calculation are described and the criteria illustrated with several examples. The extended criteria discriminate among designs equivalent by other criteria.     

Measurement biases in user involvement research

Considerable research has been conducted to demonstrate user involvement's effect on information system success. User involvement and system success typically have been measured by asking users for their perceptions of these variables. This paper reports on a field study conducted to investigate the possibility that this approach to measuring study variables tends to overstate the benefits of user involvement. The link of user involvement to user satisfaction is found to be significantly weaker when user involvement is assessed by systems analysts than when it is self reported. Further, this difference is found to be greater for systems with few users than for systems with many users. The findings suggest that common method variance and self-serving bias may have overstated the apparent benefits of user involvement in past research on information systems. Suggestions for future research are presented.     

Designs to guard against outliers in the présence or absence of model bias

Optimality of experimental design is considered in the situation in which individual observations may be subject to a shift in mean. The criterion of minimum average integrated mean square error is examined in general and the consequences for first and second degree models in the présence or absence of model bias are discussed.     

Equi-information robust designs: Which designs are possible?

The effects of missing observations in a designed experiment are reviewed. Conditions are determined for a design to retain equal information, i.e. the same generalized variance of unknown parameters, when either any single or any pair of observations is lost. Some examples of designs with this property are given. Although there are many designs which retain equal information for the loss of exactly t observations, where t = 1,2,3,…, it is shown that it is not possible to obtain any design which retains equal information when any one and any two and also any three observations are missing.     

A-Optimal Block Designs with Additional Singly Replicated Treatments

Block designs to which have been added a number of singly-replicated treatments, known as secondary treatments, are particularly useful for experiments where only small amounts of material are available for some treatments, for example new plant varieties. The designs are of particular use in the microarray situation. Such designs are known as 'augmented designs'. This paper obtains the properties of these designs and shows that, with an equal number of secondary treatments in each block, the A-optimal design is obtained by using the A-optimal design for the original block design. It develops formulae for the variance of treatment comparisons, for both the primary and the secondary treatments. A number of examples are used to illustrate the results.     

An Example Of The Use Of Andrews’ Plots To Detect Time Variations In Model Parameters And To Detect Outlying Observations

Andrews (1972) introduced a method of plotting highdimensional data in two dimensions. This method is exploited as a graphical tool for the examination of changes over time in the parameters of a time series model. An example using a Fourier series model is given to illustrate the method. It is also shown how outlying observations in the data can be found.

AMS (MOS) Subject Classifivations: 62M10, 62H30