Dr. Wahida:

If you are referring to healthcare staffing for physicians, NPs, PAs, RNs, RTs, etc, there are specific staffing ratio guidelines depending on the type of healthcare setting.  For instance, most critical care areas only allow for no more than 2 patients per RN whereas most emergency departments (ED) staff with a 3 to 4 patients per RN.  In the USA there are regional differences and my work has been on the west coast which all follow the same staffing guidelines.  Most in-patient units will staff based on the current census, where the ED will staff based on what the normal flow is throughout the department.  Hope that answers you question.

It really depends on what you want to calculate, for instance a takt time for the process or for the whole system. In healthcare, there is a lot of variability as you have rightly noted. The concept of takt time from Industrial Engineering would have to be modified to account for the variability (stochasticity). For the takt time of the overall system, for precise detail, you would need a simulation  and the takt time would be the inter-arrival times (modeled by a statistical exponential distribution for the ED). For processes, it may be modeled by a beta distribution. For less precision, simply take the demand over a large period (a month or year) and divide the time in that period by the demand (demand per year, demand per month). Remember this is just an average so you miss on variability and that can be dangerous for planning. In short, for planning purposes, it is better to think in terms of confidence intervals, e.g. 90% of the time, the takt time will be below a threshold of .....(X minutes per patient).   With this, planning can be done with that threshold. Helpful?

Wahida, try this

http://bookzz.org/s/?q=value+stream+mapping&yearFrom=&yearTo=&language=&extension=&t=0

thanks for your help. :). appreciated