On the Problems of Mixing RCTs with Qualitative Research: The Case of the MRC Framework for the Evaluation of Complex Healthcare Interventions

In the perceived hierarchy of research designs, the results from randomized controlled trials are considered to provide the highest level of evidence. Indeed these trials have been upheld as the gold standard in research. The benefits and limitations of the randomized controlled trial as a method of evaluating the effectiveness of healthcare interventions are presented. The article then examines the different levels of complexity within healthcare interventions and the problems this poses in determining effectiveness. In an effort to provide a solution to this problem, the Medical Research Council produced a framework to assist investigators to develop and evaluate complex healthcare interventions. The framework is described with reference to an example of implementing and evaluating protocols for weaning patients in the intensive care unit. The framework is critiqued on the basis that it involves an ambiguous or contradictory ontology, which fails to articulate the relationship between the positivism of randomized controlled trials with the relativism of qualitative approaches. It is concluded that the use of realist strategies in combination with randomized controlled trials provides the most coherent solution to this quandary

Healthcare professional experiences and attitudes on unlicensed/off-label paediatric prescribing and paediatric clinical trials.

Objectives: To investigate the knowledge and views of a range of healthcare professionals (consultant paediatricians, general practitioners (GPs), community pharmacists and paediatric nurses) regarding the use of unlicensed/off-label medicines in children and the participation of children in clinical trials.

Methods: A regional study in which a survey instrument with 39 items was issued to 500 randomly selected GPs, all community pharmacists (n?=?512), 50 hospital consultants and 150 paediatric nurses in Northern Ireland.

Results: Approximately half (46.5%) of the 1,212 healthcare professionals approached responded to the questionnaire. The majority of respondents indicated their familiarity with the term unlicensed (82.9%) or off-label (58.6%) prescribing with the most frequently quoted reason for such prescribing being younger age (33.6%). Apart from community pharmacists, most respondents reported having gained their knowledge through personal experience. Even though a large percentage of respondents expressed concerns about the safety (77.8%) or efficacy (87.9%) of unlicensed/off-label prescribing in children, only 30.7% reported informing parents/guardians of these concerns on the use of such medicines in children. In addition, only 56% of respondents believed that unlicensed/off-label medicines should undergo clinical trials in children. Overall, 28.4% of respondents (20.1% of GPs, 41.4% of community pharmacists, 27.7% of paediatric nurses and 94% of consultant paediatricians) indicated their willingness to be actively involved in, and recruit their patients for paediatric clinical research.

Conclusion: The use of unlicensed and off-label medicines remains a major issue in paediatric medicine. Until such times as more licensed medicines are available for children, clear guidance should be developed to allow consistency in practice across the spectrum of healthcare professionals who are involved with such medicines in their routine practice.

Performance models of storage contention in cloud environments

We propose simple models to predict the performance degradation of disk requests due to storage device contention in consolidated virtualized environments. Model parameters can be deduced from measurements obtained inside Virtual Machines (VMs) from a system where a single VM accesses a remote storage server. The parameterized model can then be used to predict the effect of storage contention when multiple VMs are consolidated on the same server. We first propose a trace-driven approach that evaluates a queueing network with fair share scheduling using simulation. The model parameters consider Virtual Machine Monitor level disk access optimizations and rely on a calibration technique. We further present a measurement-based approach that allows a distinct characterization of read/write performance attributes. In particular, we define simple linear prediction models for I/O request mean response times, throughputs and read/write mixes, as well as a simulation model for predicting response time distributions. We found our models to be effective in predicting such quantities across a range of synthetic and emulated application workloads.