There are two simple ways to categorise dashboards - exploratory or explanatory. Explanatory dashboards aim to guide a user through a story, drawing attention to key insights which contribute to the overall message. Exploratory dashboards on the other hand, allow the user to decide how much investigating they want to do; how many (or few) insights they want to take away.
Is one format better?
As with many things, the answer is it depends. So, when would we want to use which type of dashboard?
Exploratory dashboards can be more appropriate in cases where we don't have a set or singular question we are trying to answer. The lack of one direct question gives the user more control to find their own questions and answers. It is a good way to explore the data, and this can then generate questions for further investigation through a more explanatory format.
A good example of an explanatory dashboard is this one which can be explored on Tableau Public. This dashboard shows World Cup penalty shootouts and allows the user to explore where successful or unsuccessful penalties have landed.
On the other hand, explanatory dashboards can be more appropriate when we are trying to carefully tailor the content to answer a question or a set of questions. The below visualisation, which can be viewed in full on Tableau Public, follows a story format which takes the user through some key insights on different countries' progress towards net zero. The content is carefully tailored and laid out to follow a narrative which leads the user to towards the desired conclusion. The visualisations selected for the dashboard all contribute towards this same narrative.
This has a very different impact and use compared to an exploratory dashboard.
As per their respective names, you should lean towards exploratory dashboards when you want the user to be able to explore and make their own conclusions or find independent insights, whilst you should lean towards explanatory dashbords when you want to tailor the content for a set audience with specific questions.
A good approach is to focus on the user story before getting too bogged down in exploratory versus explanatory formats. The user story will determine which way the dashboard should lean, and in many cases, the dashboard will contain elements of both formats.