Finison, Lorenz J.; Spencer, Maureen; Finison, Karl S. (1993, ASQC) New England Applied Research Group; Boston, MA
The measure of days between infections (DBI) is an alternative to infection rate when determining if an epidemic is present. Individuals charts with moving range limits and statistical transformations enhance the DBI measure. DBI is especially useful when collecting data on nosocomial infections acquired as a by-product of hospitalization. Typical nosocomial infections are pneumonia, bacteremia, and urinary tract infections. Traditional measures of infection rates make it difficult to detect early signs that these infections are epidemic. DBI data are more sensitive to early detection, especially when plotted on an individuals chart with moving averages. Two examples are given for clostridium difficile in a small hospital and a large hospital. DBI data often are non-normal, as they are in the two examples. A square root transformation can normalize the data, though more radically non-normal data may need a fourth root transformation. Training for use of these techniques requires changing the non statistical culture of the health care organization.
Individuals charts,Statistical quality control (SQC),Control charts