Health economics and psychiatry: the pursuit of efficiency

The Landmark is a drop-in day centre for people with AIDS/HIV situated in South London. Determination of the number of people visiting and the length of stay was a necessary component in establishing the unit cost of this centre. However, it did not prove practicable to measure directly the length of time that individuals spent at the centre. An elaborate registration systems or close observation would have run counter to the open-door ethos that the centre wished to establish. This paper presents a method of estimating average length of stay based on observations of the number of people entering and the numbers present at various times of the day, counts that in practice were relatively easy to make.