Decision Tree Exercise

A participant-led group exercise. The goal is to work through scenarios and surface the questions that matter when choosing how to handle reporting delays and other data challenges. The output will help inform the interactive decision tree.

How it works

Pick a scenario closest to your own setting, or bring your own. As you work through it, sketch out a decision tree that captures the choices you would make and why.

Step 1: Define your starting point

  • What data do you have?
  • What challenge are you facing?
  • What do you need to deliver and how quickly?

Step 2: Sketch your decision tree

Work through the choices you would make, branching at each decision point. For example:

  • Are delays stable or changing?
  • Do you have enough historical data to estimate delay patterns?
  • Do you need uncertainty estimates or just a point correction?
  • How much time and technical capacity do you have?

Write or draw your tree as you go. It does not need to be neat; the goal is to capture the logic.

Step 3: Compare and discuss

Share your tree with the group. Where do your trees agree? Where do they diverge and why?

Example scenarios

These are starting points; use your own data and challenges if you prefer.

  • Weekly syndromic surveillance with stable delays: weekly ED visit counts for respiratory illness, typically complete within two weeks, stable delay pattern, need to report trends each Monday.
  • Daily case counts during an emerging outbreak: daily counts by symptom onset, delays getting longer as labs come under strain, leadership wants daily updates.
  • Site drop-in/drop-out in sentinel surveillance: hospitalisations across 12 sentinel sites, two reporting intermittently, one new site, need a jurisdiction-wide estimate.
  • Low counts with long delays: rare condition with 5-10 cases per week, delays up to 6 weeks, 18 months of historical data.

What to capture

As you sketch your tree, note:

  • What questions determine the next branch?
  • What information do you need at each decision point?
  • Where is the boundary between “simple enough” and “need something more formal”?
  • Are there dead ends where no current tool fits well?