Patient days attempts to convey information concerned with how many patients have been treated by a facility or plan. There are at least six different calculations according to an article in Nursing Management; the preferred method is actual hours for inpatients and short stays.
According to Nursing Management, six calculations of patient days are: daily midnight census; daily midnight census with additional patient days from actual hours for short-stay patients; daily midnight census with additional patient days from average hours for short-stay patients; actual hours for inpatients and short-stay patients, multiple calculations from multiple census reports; and daily midnight and noon census. There are known biases for each calculation method. The calculation for actual hours for inpatients and short-stay patients is the best method that has demonstrated the least bias and is described as "gold standard."