Examining rounding error in least absolute values regression computations

Two techniques for detecting inaccuracies in least absolute values (LAV) regression computations are presented and discussed. Examples of the use of the methods are given. The techniques are shown to apply to the more general case of M-estimation.     

A suggestion for measuring heteroskedasticity

The lack of a generally-accepted measure of the degree of severity of heteroskedasticity is shown to have caused some Monte Carlo studies to draw misleading conclusions. An attractive measure of heteroskedasticity is suggested.     

Accurate probabilities for the sign test

Limitations in currently available methods for producing significance probabilities for the sign test are discussed. Two simple modifications to the continuity corrected normal approximation are derived and presented in a simple form. These modifications are shown to markedly reduce the relative error in approximating exact probabilities. The relative simplicity of these modifications and the importance of accurate p values suggest that one or both modifications could be useful improvements.     

Citizenship and Governance in the Asian Region: Insights from The International Civic and Citizenship Education Study

Large scale assessment of student performance is a regular feature of the international education landscape. The International Civic and Citizenship Education Study (ICCS) is a recent attempt with a focus on citizenship knowledge and skills. Student political trust data from ICCS is reported here and a mixture Rasch model is used to identify the heterogeneity in this data. The results indicate the complexity of within country and cross-country estimates of measures of political trust. The problem of relying on a single scale score to represent this complexity is underscored and the implications for citizenship education are discussed.