Which feature in Tableau Prep can be used to fill gaps in daily event data?

The feature in Tableau Prep that is used to fill gaps in daily event data is New Rows. This option allows users to create additional rows in their dataset based on the unique values of a specified key, often within a date range. By utilizing New Rows, you can generate a complete set of entries for each day within the specified time frame, even if there are no corresponding records for some days in the original data. This makes it particularly useful for datasets involving daily events where some dates may have missing entries.

In contrast, calculated fields are primarily used to create new data fields derived from existing data through functions and calculations, rather than addressing missing data directly. Joins merge data from different tables based on a common field but do not inherently introduce new rows for missing date entries. The Group By feature aggregates data based on specified dimensions and is not designed to fill in gaps within the dataset.

Overall, New Rows is essential for ensuring a complete timeline for daily event data, allowing for better analysis and visualization in Tableau.