A new model for the length of stay of hospital patients.

Hospital Length of Stay (LoS) is a valid proxy to estimate the consumption of hospital resources. Average LoS, however, albeit easy to quantify and calculate, can be misleading if the underlying distribution is not symmetric. Therefore the average does not reflect the nature of such underlying distribution and may mask different effects. This paper uses routinely collected data of an Italian hospital patients from different departments over a period of 5 years. This will be the basis for a running example illustrating the alternative models of patients length of stay. The models includes a new density model called Hypergamma. The paper concludes by summarizing these various modelling techniques and highlighting the use of a risk measure in bed planning.