Standard Error of Measurement

The standard error of measurement (SEM) is the standard deviation of errors of measurement that are associated with test scores from a particular group of examinees. When used to calculate confidence bands around obtained test scores, it can be helpful in expressing the unreliability of individual test scores in an understandable way. Score bands can also be used to interpret intraindividual and interindividual score differences. Interpreters should be wary of over-interpretation when using approximations for correctly calculated score bands. It is recommended that SEMs at various score levels be used in calculating score bands rather than a single SEM value.     

The Concept of Inclusive Education: Teacher Training and Acquisition of English Language in the Hearing Impaired

Three languages are widely used in schools in Kenya – English, Kiswahili and Kenya Sign Language. Many pupils with hearing impairments are taught separately from the mainstream, in specialist settings. The fact that most of the formal teaching, assessment and examination processes in Kenyan schools rely upon spoken and written English compounds the separation of these pupils from the mainstream of education and, potentially, from the mainstream of society. In this article, Gertrude Wamae, graduate assistant in the Department of English and Linguistics at Kenyatta University, and Rachael Kang'ethe-Kamau, lecturer in the Department of Special Education at Kenyatta University, discuss the relationships between language, hearing impairment and inclusion in the Kenyan context. The article suggests that the use of signed exact English would enhance opportunities for inclusion for those with hearing impairments and that programmes of teacher training need to take account of persuasive research in this area. The article closes with a plea for further research, carried out collaboratively by educationalists, linguists, teacher trainers and practitioners, to develop policies and practices suited to more inclusive futures. The article is based on a paper presented to the International Conference on Inclusive Education run by Maseno University in September 2002.     

Environmentally-induced stone decay: the cumulative effects of crystallization–hydration cycles on a Lincolnshire oopelsparite limestone

An investigation has been undertaken at St Andrew’s church, Walpole St Andrew, Norfolk, to establish the underlying causes of the observed stone decay to the upper parts of the six stone piers. The stone decay was first recorded in the early 1930s. The salt-contaminated masonry within the church has been shown to undergo severe salt decay during the summer, with little damage occurring over the winter months. The south aisle piers have been shown to decay 2.5 times faster than the north aisle piers. Although crystallization–hydration cycles have been identified, the rate of decay is at its greatest when the cycling is relatively infrequent. This was not the expected trend. Furthermore, it has been shown that during extended periods where the ambient relative humidity is less than 75%, the rate of decay reaches a maximum. It is the length of this ‘drying’ period that apparently has the greatest influence on the rate of decay and could explain the significant difference in the rate of decay between the south and north aisle piers. The results have serious implications for passive conservation, where it is often recommended to lower the ambient relative humidity to well below the equilibrium relative humidity of the salt contaminant, to avoid crystallization–hydration cycles. Since, at the time of building, the church was situated on the coast, it is possible that the sodium chloride contamination occurred during the building process (1440–1520), particularly since the area was prone to sea-flooding at this time. Alternatively, the salt could have been applied as a treatment during the general restoration of 1897. Whatever the source of the salt, it seems likely that the ambient environment was changed by the insertion of a sealed floor in 1897, which could account for the onset of the salt decay.     

Educational and Employment Testing: Changing Concepts in Measurement and Policy

How will the expansion of the concept of construct validity affect validation practice in employment testing? How does the need for consequential validity differ in educational and employment testing? How do the research bases differ for performance assessment in these settings? Are there parallel trends in policies for test use in education and industry?