One of the fun things about doing observations in a hospital is that you see lots of unexpected things. When observing surgeries or patient consultations in the outpatient department I was introduced to doctors and nurses. After been told what my background was (systems engineer/consultant) some asked whether I was going to investigate how efficient they really worked (‘uh no, not really’). At the same time many classified their hospital as a ‘production hospital’. Based on this I got the impression that this indeed was a factory in which patients are treated in a smooth and standardized process. In the observations I was surprised that nurses and doctors were very much focussed on being on time and organizing tasks as efficient as possible, even when the circumstances obstructed this. This could be because I was there (you never know) but I don’t really think so, given the many times I was in the hospital. The more surprised I was when I analyzed the ‘production data’.
This figure shows the yearly volume of all surgery codes and how much variation there is in surgery time (standard deviation as a percentage of the average surgery time). First of all there are many surgeries that are performed less than 100 times a year (less than twice a week). There is one type of surgery that is performed over 700 times a year. Secondly most surgeries have a variation in surgery time between 20% and 60%.
Further I discovered that there are 187 unique routings for 10,000 surgery patients, from outpatient deparment to discharge from the ward after the surgery took place. There are 2881 unique combinations of medical instruments being used for surgeries and 7640 unique combinations of people participating in one surgery.
This apparent variability is interesting because it does not seem to reflect the factory metaphor at all. In a factory such variability would be challenging (if not impossible) for mass production or even mass customization. According to Johnston et. al. [1] high variation and low volume processes require a high decision making autonomy and flexible interaction between people. This may be reflected in the social networks I made. Lean and Six Sigma focus on standardization and variability reduction, an approach that fits a process with low variability and high volume, according to Johnston et. al. [1]. Following this reasoning perhaps lean/six sigma are not the panacea we are all hoping for.
However, this conclusion is premature. First of all we don’t know what causes this variation: is it caused by patient demand and/or caused by the hospital itself? Is the autonomy of doctors the cause or the effect of variation? Is variation avoidable or would we be able to reduce it? Another issue are the data; do the 394 surgery codes really represent completely different types of surgeries? Without central master data management for surgery codes, there could be multiple codes for the same type of surgery. If that is the case, then production volumes shown here are too low. In conclusion, further research is recommended…..
[1] See this paper of Henri Boersma, Tiffany Leung, Rob Vanwersch, Elske Heeren and Frits van Merode