Often in tableau you’ll find you need a filter that’s neither local of global, you will want a dashboard level filter. On a dashboard local filters are often too restrictive as they only alter 1 part of the dashboard, and to have 2 identical local filters on a dashboard also isn’t a valid option. To overcome that problem filters can also be global. This also comes with problems every worksheet from that data source is also forced to share that filter when you often don’t want to.
Currently there isn’t a dashboard level filter – i.e. a filter that’s local to everything on the dashboard only without affecting any other dashboards created from the same data source.
In some circumstances in Tableau 6 it’s possible to create a dashboard level filter using parameters as a substitute filter. Note using a parameter removes some of the built-in filter functionality such as selecting multiple options in a filter or having a select All option, the parameter is only a valid substitute when selecting a single value.
To create the dashboard level filter first of all create a parameter based on a field. For this example I want to be able to filter for a specific month. I’m going to create a parameter with Data Type ‘Date and time’ and format the month with a Custom format of ‘mmmm’ which gives a display of January, February, etc. and populate the parameter with a List from a Field called StartOfMonth.
Next create a calculated field to act as out filter. This is setting the month of the value selected in the parameter to be the same as the month in your dataset.
You need to drag this calculated field, MonthFilter, into the Filters area on the worksheet and set the value to True.
To make this parameter able to filter all worksheets on your dashboard just simply drag this MonthFilter field into the Filters section of all worksheets that will be displayed on the dashboard and set the value to True. Now create your dashboard and when you change the value in the parameter it will change all of the worksheets. In other words it’s a dashboard level filter.
NOTE: When published on to the server this didn’t work properly, perhaps due to a Tableau server bug, but I’m really not sure. Anyway, the work around is here.