Evaluating Case Investigation and Contact Tracing Success

Updated May 26, 2020

Routine review of both process and outcome metrics will also be crucial for case investigation and contact tracing success.  By examining these data regularly, issues can be identified and rapidly addressed, changes to internal case investigation and contact tracing processes can be made, and the local health authority can more easily pivot when new high-risk populations are identified.  The uses of data related to case investigation and contact tracing fit broadly into four main domains:

  1. Individual case investigation and contact tracing supervision and management
  2. Programmatic process measures
  3. Programmatic outcome measures
  4. Ad-hoc epidemiologic and other public health analyses

Here we will focus on the first three mentioned above.

During case investigations and contact tracing, it takes time to identify and interview clients and then counsel and test all contacts.  Examining “live” data for evaluation can lead to spurious or false inferences as there has not been enough time to finish and close out open or pending investigations.

Consider adding a lag period to all reports or data runs to ensure that partial or ongoing investigations are not being included in reports and metrics.

Also consider setting targets for select process and outcome metrics (especially for timeliness of patient and contact notification and self-isolation/self-quarantine) to guide adjustments to policies and protocols.

Individual case investigation and contact tracing supervision and management

To support supervision of case investigation and contact tracing staff, canned reports at the level of the individual case investigator and contact tracer will help ensure that staff are meeting expectations and identify areas for additional training.  Reports can be produced for a 2-week review period and could include:

  • Number of case investigations assigned during review period
  • Number of clients interviewed during review period
  • Number and percentage of clients interviewed <24 hours from report to health authority during review period
  • Number of case investigations closed during review period
  • Number and percent of case investigations in which at least one close contact was elicited during review period
  • Median number of days from assignment of investigations to interview during review period
  • Total number of contacts elicited from case investigations during review period
  • Median number of contacts elicited from clients per case interview during review period, among cases where at least one contact was elicited
  • Number of contacts notified during review period and percent out of total number of contacts named
  • Total number of contacts interviewed/total number of contacts named by cases during review period
  • Median number of days from initiation/assignment of contact to notification during review period
  • Number of cases who completed isolation/total number of cases advised to isolate during review period
  • Number of contacts who completed quarantine/total number of contacts advised to quarantine during review period
  • Number of referrals to social support
  • Number of referrals for clinical consultation

Programmatic process measures

Data examined among all case investigation and contact tracing staff will help provide leadership with insights into program successes and possible opportunities for additional training, resources or focus areas.  These can be canned reports that are produced regularly (bi-weekly or monthly).  These measures could include:

  • Number of case investigations assigned during review period
  • Number of clients interviewed during review period
  • Number and percentage of clients interviewed <24 hours from report to health authority during review period
  • Number of case investigations closed during review period
  • Number and percentage of clients who named at least one close contact during review period
  • Median days from receipt of report to interview during review period
  • Total number of contacts elicited among case investigations during review period
  • Total number of contacts interviewed/total number of contacts named by cases during review period
  • Median number of contacts named per patient interview during review period
  • Number of clients who completed isolation/total number of clients advised to isolate during review period
  • Number of contacts who completed quarantine/total number of contacts advised to quarantine during review period
  • Number of referrals to social support
  • Number of referrals for clinical consultation

Programmatic outcome measures

  • Number of clients interviewed/Number of case investigations
  • Number of contacts tested for SARS-CoV-2/Number of contacts interviewed
  • Number and percentage of new confirmed COVID-19 cases arising from quarantined contacts
  • Number of contacts self-quarantined as a result of contact tracing
  • Number and percentage of clients who completed full self-isolation period
  • Number of contacts who completed 14-day self-quarantine/notified contacts