As others have posted "FTE" stands for "Full Time Equivalent," which is the most common unit of measurement for preparing a budget. It refers to one person working 40 hours per week. Someone who works 20 hours per week occupies a 0.5 FTE position in the budget, etc. Depending on the amount of vacation time, sick time, etc. calculated into the equations, it takes between 3.5 FTE's and 4.0 FTE's to have 1 nurses per shift around the clock all week.
The concept of acuity is used (and sometimes measured) to determine how many nurses you NEED per shift -- regardless of how many nurses you actually have available. Many different tools are available to measure acuity as it used to be a JACHO requirement that hospitals do so regularly and base their staffing on a system that took acuity into account. However, acuity is a VERY tricky concept to measure and to deal with because there are so many nuances involved. For example, some patients require a lot of time with their basic activities of daily living, but are actually very stable and much of that care could be provided by an LPN or aide. Other patients may be very unstable and require a lot of sophisticated nursing judgement, but might not be quite so time-consuming. Other patients require a lot of nursing attention because of their family's needs, or teaching needs, etc. while others have a lot of lab work and they are a "difficult stick." The acuity systems have big problems distiguishing between the different TYPES of acuity and therefore have declined somewhat in their popularity.
Another problem with the use of acuity systems on a daily basis is the time it takes for the staff to accurately calculate each patient's acuity each shift. Some systems add a tremendous burden to the workload.
Another problem is with insurance companies. Some started using acuity numbers to determine how much they would pay for that day in the hospitals. That increased the burden on the hospital (and the staff) to document and justify why the patient was classified as he/she was.
Also, computer companies saw an opportunity to make money developing and selling systems that combined acuity scoring with schedule making, payroll, etc. Once a hospital has invested lots of money on an expensive computer system, they are going to want to stick with it even if it is not perfect.
Currently, JCAHO does not require the use of an acuity scoring system as it once did ... though it does require some assessment of the patients' needs and a system for matching needs with staffing patterns. Nurse managers and scholars are still struggling with trying to develop a way to accurately measure patient needs so that those measurements can used to guide staffing decisions. But there is still a long way to go.
Final note, it's not just the acuity measuring tool that you use that counts .... it's how you use the system you have ... and what you do with the information it gives you.
llg -- who's been around the block with this stuff more than a few times.