Understanding Denominator Presentation

Denominators can be compared to numerators in a variety of ways, as described in the table below.

Note: In order to view the table, you must check the Include Table box in the Chart Type section (Selecting the Chart Type).

Table 12-5: Understanding Denominator Presentation
Type	Description	Sample
Time Period	When a `Time Period` selection is made for the Compare As field, all other fields in the Denominator section are hidden. There are two different time period selections: Equivalent Time Period Year – uses numerator settings to create the denominator for the same time period but in the previous year. If running the report for the first three months of 2010, the denominator will be for the first three months of 2009. Previous Time Period – uses numerator settings to create the denominator for the same amount of time leading up to the report start date. If running the report for August and September, for example, the denominator will be from June and July; or when running the report for the last six months of the year, the denominator will be for the first six months of the year. The denominator values are shown in the parenthesis for each cell in the table and are not included in the chart.
Rate	Combines the numerator and denominator to calculate a rate. In this example, you see that the y‑axis values are numbers before the denominator is added; when a `Rate` denominator is applied to the report, the values along the y-axis are changed into percentages. The y-axis label is also changed to include the word “rate.” In this example, however, a custom axis label has been entered. If a table has been added to the report, the denominator values are shown in parenthesis.
Separate	Plots the denominator on a different chart below the numerator. In this example, the denominator shows the number of central line insertions while the numerator shows how many bloodstream infections have been documented for the same time period. If a table has been added to the report, the denominator values are shown in parenthesis.
Side By Side	Plots the denominator on the same chart as the numerator. In this example, the numerator tracks the number of bloodstream infections and the denominator shows the number of central line insertions. Tip: When plotting the numerator and denominator on the same chart, be sure to provide a descriptive axis label (Show Section Field Descriptions).
Standardized Infection Ratio (SIR) Report	The SIR compares the actual number of HAIs with a baseline population. A SIR greater than 1.0 indicates that more HAIs were observed than predicted; less than 1.0 indicates fewer than predicted (CDC). In this example, the numerator is bloodstream infection associated events and the denominator shows the standardized infection ratio.