No abstract

OR case scheduling can be improved by using the 3-parameter lognormal model with surgeon effects and by using surgeons' prior guesses for rarely observed CPTs. Using the 3-parameter lognormal model for case-duration prediction and scheduling significantly reduces both the prediction error and OR inefficiency.

The effectiveness of safety inspections has been analysed from various angles, but until now, relatively little attention has been given to translate risk reduction into incident cost savings. This paper quantifies estimated cost savings based on port state control inspections and industry vetting inspections. It is based on a unique dataset of 515,194 ship arrivals and inspections from the United States of America and Australia, and inspections of three industry vetting inspection regimes, for the time period 2002 to 2007. The risk reducing effect of inspections is estimated by means of duration models, in terms of inspection gains based on the probability of survival. The results suggest average total estimated cost savings in the range of USD 74 to 192 thousand (median USD 19 to 46 thousand) owing to reduced risk of total loss due to a port state control inspection. Cost savings for industry inspections are found to be even higher, especially for tankers. The savings vary by type, age and size of the ship. The benefits of an inspection are in general larger for older and larger vessels, and also for vessels with undefined flags and unknown classification societies. As inspection costs are relatively low in comparison to potential cost savings, the results underline the importance in determining high risk ships to prevent costs due to total loss of ships.

Working with fixed teams in bariatric surgery reduced procedure durations and improved teamwork and safety climate, without adverse effects on patient outcomes.

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Global trade depends for a large part on maritime transport, and safe ships are needed not only to protect precious cargo but also to prevent environmental damage. Flag state and port state authorities spend much effort in ship safety inspections to ensure a minimum safety level and to prevent casualties. This paper investigates the safety gains of current inspection

This paper puts forward kernel ridge regression as an approach for forecasting with many predictors that are related nonlinearly to the target variable. In kernel ridge regression, the observed predictor variables are mapped nonlinearly into a high-dimensional space, where estimation of the predictive regression model is based on a shrinkage estimator to avoid overfitting. We extend the kernel ridge regression methodology to enable its use for economic time-series forecasting, by including lags of the dependent variable or other individual variables as predictors, as typically desired in macroeconomic and financial applications. Monte Carlo simulations as well as an empirical application to various key measures of real economic activity confirm that kernel ridge regression can produce more accurate forecasts than traditional linear methods for dealing with many predictors based on principal component regression.

Accurate prediction of medical operation times is of crucial importance for cost-efficient operation room planning in hospitals. This paper investigates the possible dependence of procedure times on surgeon factors like age, experience, gender and team composition. The effect of these factors is estimated for over 30 different types of medical operations in two hospitals, by means of ANOVA models for logarithmic case durations. The estimation data set contains about 30,000 observations from 2005 to 2008. The relevance of surgeon factors depends on the type of operation. The factors found most often to be significant are team composition, experience and time of the day. Contrary to widespread opinions among surgeons, gender has nearly never a significant effect. By incorporating surgeon factors, the accuracy of out-of-sample prediction of case durations of about 1250 surgical operations in 2009 is improved by up to more than 15% compared with current planning procedures.