The Public Data Explorer works best with data that are:
- Quantitative: Each data point has one or more numeric metrics associated with it (e.g., "population", "number of flu cases", "revenue").
- Categorical: Data can be organized into a finite number of text-describable categories (e.g., "countries", "genders", "age groups").
- Time series: For each category, the data metrics vary as a function of time, and adjacent points are at least one day apart (the Public Data Explorer cannot visualize time increments smaller than a day).
- Aggregated: For each time / category / metric combination, there is a single data point, not a list of events or facts.
In particular, note that unaggregated "fact" or "event" data may be importable, but will not produce interesting visualizations.