Incidence tile (r9)

The Incidence tile allows users to review the incidence completion rates (also known as the "IR") of respondents coming into the survey over time. The timeframe can be customized, and the data can be displayed as a line chart or a grid.

The tile appears on the Metrics tab of the Fielding Overview applet.

Overview

By default, the Incidence tile displays a line chart of incidence calculations over a given period of time. The Incidence Rate (%) is displayed on the vertical (Y) axis with time on the horizontal (X) axis, defaulting to the previous 24 hours. The graph has four lines, each using a unique formula for calculating incidence. 

These can show the effectiveness of the sample targeting and screener questions, helping to answer questions such as:

• Are we inviting the right people?
• Are our screener questions too strict or too relaxed?

The following incidence rate calculations are displayed on the tile, where C = the number of Completes; T = the number of Terminated respondents; and Q = the number of respondents Over Quota. In each case, the selected time frame will be broken into equal time intervals.

• Average IR C/(C+T) (purple) is the average incidence rate since the prior time marker (data point) on the line. 
• Average IR C/(C+T+Q) (green) is the average incidence rate since the prior time marker on the line. This is similar to the purple line calculations, but also adds in the number of Over Quota (Q) respondents to the denominator.
• Overall IR C/(C+T) (orange) is the overall incidence rate as accrued during the currently displayed time interval (e.g., 24 hours), beginning with any already-accrued data since the start of fielding.
• Overall IR C/(C+T+Q) (red) is the overall incidence rate as accrued during the currently displayed time interval (e.g., 24 hours), beginning with any already-accrued data since the start of fielding. This is similar to the yellow line calculations, but also adds in the number of Over Quota (Q) respondents to the denominator.

You can read more about respondent statuses in Understanding respondent statuses (r9).

Understanding overlapping lines

Occasionally, there may be overlap between the lines in the chart. Hovering over each color in the key below the chart allows you to see all of that line's data points.

In the below screenshot, the purple line (Average IR without Over quotas) is highlighted to show where it overlaps with the green line (Average IR including Over quotas). The quotas began to reach their maximums during the timeframe of the chart, so the two IR calculations diverge at the last two nodes.

Exploring different time intervals

In the top-left of the tile, you can utilize the Select interval menu to select from an assortment of time spans. The time intervals range from 6 hours to 2 weeks. The default is 24 hours. Each interval is divided into eight equal timestamps relative to the interval selected. The times shown are in Pacific Time (GMT-7).

Customizing an endpoint

Users may also select an end point for the survey's response data other than the most recently updated time. Click the Select endpoint menu and choose from Last complete, Last activity, Now, or Date. If Date is chosen, a calendar will appear, allowing you to select any date up until the current date. 

Applying a customized endpoint will shift the graph's data points based on the selection.

Chart View vs. Grid View

By default, the Incidence tile displays in Chart View. Click the  Gear menu button and select Grid View to see the exact values represented by the lines in Chart View. There are four columns, one for each IR calculation.