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Abstract Background Cronbach's alpha is widely used as the preferred index of reliability for medical postgraduate examinations. A value of 0.8-0.9 is seen by providers and regulators alike as an adequate demonstration of acceptable reliability for any assessment. Of the other statistical parameters, Standard Error of Measurement (SEM) is mainly seen as useful only in determining the accuracy of a pass mark. However the alpha coefficient depends both on SEM and on the ability range (standard deviation, SD) of candidates taking an exam. This study investigated the extent to which the necessarily narrower ability range in candidates taking the second of the three part MRCP(UK) diploma examinations, biases assessment of reliability and SEM. Methods a) The interrelationships of standard deviation (SD), SEM and reliability were investigated in a Monte Carlo simulation of 10,000 candidates taking a postgraduate examination. b) Reliability and SEM were studied in the MRCP(UK) Part 1 and Part 2 Written Examinations from 2002 to 2008. c) Reliability and SEM were studied in eight Specialty Certificate Examinations introduced in 2008-9. Results The Monte Carlo simulation showed, as expected, that restricting the range of an assessment only to those who had already passed it, dramatically reduced the reliability but did not affect the SEM of a simulated assessment. The analysis of the MRCP(UK) Part 1 and Part 2 written examinations showed that the MRCP(UK) Part 2 written examination had a lower reliability than the Part 1 examination, but, despite that lower reliability, the Part 2 examination also had a smaller SEM (indicating a more accurate assessment). The Specialty Certificate Examinations had small Ns, and as a result, wide variability in their reliabilities, but SEMs were comparable with MRCP(UK) Part 2. Conclusions An emphasis upon assessing the quality of assessments primarily in terms of reliability alone can produce a paradoxical and distorted picture, particularly in the situation where a narrower range of candidate ability is an inevitable consequence of being able to take a second part examination only after passing the first part examination. Reliability also shows problems when numbers of candidates in examinations are low and sampling error affects the range of candidate ability. SEM is not subject to such problems; it is therefore a better measure of the quality of an assessment and is recommended for routine use.

A human complementary DNA clone, designated AML1 because it marks a subtype of acute myeloid leukemia, is the homologue of runt, one of a group of pair-rule genes that determines morphogenesis in the fly Drosophila melanogaster. The area of homology linking the Drosophila and human polypeptide sequences extends to the conserved exon/intron boundary. Further research is needed to establish AML1's effect on human development.

Background and Objectives: The prognosis in patients with primary refractory or relapsed high grade non-Hodgkin's lymphoma (NHL) is very poor--the 5-year survival being generally reported at 10%., Design and Methods: Multiple salvage regimens have been investigated and, while response rates of 50-80% have been noted in selected patients, the long-term prognosis remains poor. Following the encouraging results in high risk Burkitt's and Burkitt-like lymphoma using the CODOX-M and IVAC protocols, we performed a pilot study using a similar regimen in patients with primary refractory or relapsed high grade NHL., Results: The regimens were modified by a reduction in the intensity of intrathecal therapy. It was planned to mobilize peripheral blood stem cells following the IVAC cycle for use in subsequent autologous peripheral blood stem cell transplantation in chemosensitive patients. The initial plan was to recruit 50 patients, but the study was closed after 8 due to excessive toxicity., Interpretation and Conclusions: We conclude that the CODOX-M/IVAC regimen is too toxic for this group of patients and does not result in better response rates than those to currently available salvage regimens.