How do you identify a trend in a run chart of hospital-acquired infections?

• A. Focus only on the most recent data point.
• B. Look for nonrandom patterns, shifts, or sustained runs; use statistical rules and escalate if needed.
• C. Count total infections per year only.
• D. Ignore shifts and assume randomness.

Answer: (B)

When monitoring hospital-acquired infections over time, the goal is to tell whether observed changes reflect real shifts in the process or just random variation. A run chart helps by plotting infection data in chronological order and highlighting patterns that aren’t random. The best approach is to look for nonrandom patterns such as a trend (a streak of points that consistently rise or fall) or a shift (a sustained change in the level, where many consecutive points sit above or below the previous center). Also pay attention to sustained runs where several points stay on one side of the center line. Using simple statistical rules to judge when these patterns are unlikely due to chance lets you determine if investigation or action is warranted, and you escalate to infection control when such patterns appear.

Focusing only on the most recent data point misses the bigger picture and can overlook a developing trend. Counting infections per year removes the temporal sequence needed to see patterns. Ignoring shifts and assuming randomness would cause you to miss meaningful changes in the infection rate.