Comparing results to baseline
Pressing on any value in Protobi creates a filter that applies to every element. This enables you to see how respondents who answered one question answered other questions. Press anywhere to filter everywhere.
Protobi automatically compares every result to a baseline distribution so that you can immediately see important differences and quickly test hypotheses.
But wait... how do we compare what's different? That's typically the first question. That's what baseline is for. In this tutorial we will teach you how to view your baseline, then dive deeper into its significance.
Quick start guide:
- Press to create filters for defining one scenario (see Press to query)
- Press "Set base" to set the current scenario as the baseline
- Press to create filters for another scenario
- The solid bars now represent your new scenario
- The thin black outlines represent your baseline scenario
- Triangles indicate significant differences between current and baseline
Initial view
When you first open a dataset in Protobi it displays results for all respondents. Below are the first two questions from the Gender and Generations Survey from Pew Research.
We can see 30.5% of all respondents say they are "Very happy," and 25.4% say they are in "Excellent" health.
Press to filter
Press on "Excellent" in q2 to show results for just those respondents. We can see out of the 100% of respondents who reported themselves in "Excellent" health, 49.6% also said they are "Very happy."
Here you can observe there are thin black outlines and solid color bars .
The percentages and solid color bars reflect the current scenario, (i.e., only those in "Excellent" health). The thin black outlines reflect the baseline scenario (which initially includes all respondents).
You can hover to see the value baseline frequency. Here, of those in "Excellent" health, 49.6% are "Very happy" compared to 30.5% for all respondents.
Protobi shows blue triangles wherever the current scenario is significantly different from baseline. Here, the triangle indicates that 49.6% is significantly higher than 30.5%.
Protobi is smart enough to recognize that "Very happy" respondents are a subset of all respondents, so in this case the triangle is really comparing "Very happy" to not "Very happy" respondents.
Set current filters as baseline
But let's say we want to make a strict comparison between non-overlapping groups, to compare those respondents who are NOT in "Excellent" health to those who ARE in "Excellent" health.
Press the toolbar button "Set base" to make the baseline scenario equal to the current scenario:
Select other filters
Now shift+press on "Excellent" to select those respondents who are NOT in "Excellent" health:
We can see above, we're now running a strong comparison between two distinct groups. The groups being those who are NOT in "Excellent" health (current scenario, solid bars) versus those who ARE in "Excellent" health (baseline scenario, thin black outline).
See also
Baseline scenarios are great for comparing specific subsets. But if your goal is to systematically compare every value, another approach is to create a crosstab:
