Reed, W. Robert; Webb, Rachel S. - In: Economics - The Open-Access, Open-Assessment E-Journal 5 (2011), pp. 1-14
Non-spherical errors, namely heteroscedasticity, serial correlation and cross-sectional correlation are commonly present within panel data sets. These can cause significant problems for econometric analyses. The FGLS(Parks) estimator has been demonstrated to produce considerable efficiency gains...