Which of the following should be included when designing a data collection form for surveillance?

The Certification Study Guide (6th edition) emphasizes that effective surveillance depends on the ability to calculate rates, not just counts. To calculate any infection rate, both a numerator (number of infection events) and a denominator (population at risk or time at risk) are required. Therefore, inclusion of denominator information is essential when designing a data collection form for surveillance.

Denominator data may include patient days, device days (e.g., central line days, ventilator days), number of procedures, or number of admissions—depending on the surveillance objective. Without denominator data, infection preventionists cannot calculate standardized rates, compare trends over time, or benchmark against national databases. The study guide clearly states that surveillance systems lacking denominator data produce incomplete and potentially misleading results.

The other options are either vague or inappropriate. While data collection forms should avoid unnecessary information, simply stating “only the information needed” does not address the critical requirement for denominator data. Collecting “as much information as possible” is discouraged because it increases workload, reduces data quality, and may compromise sustainability of surveillance programs. Medication history is not routinely required for most surveillance activities unless it is directly related to the infection being studied.

This question reflects a fundamental CIC exam principle: surveillance must be designed to support valid rate calculation and analysis. Including denominator information ensures that collected data are meaningful, actionable, and aligned with evidence-based infection prevention practices.