Criteria selection : use empty for ALL?

Question

We have the following criteria screen. Based on these criteria data are fetched. Empty From/To Date field means that no date criteria will be used, but for the type criteria we have two options :

1. Add an item ALL in the list
2. Add an empty item in the list which will mean that no type criteria will be used.

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Which option is better for the user to understand and use ?

Answer 1

I'd suggest you go with the empty item. For two reasons:

1. To be consistent with your criteria options. Why should a user have to leave the date fields empty to get the complete range but have to select an option when it comes to types
2. You usually refine your search by applying filters. Selecting "All" does not refine your search result whereas selecting a different value of the dropdown does.