The Time estimation of a dashboard development in Tableau will be dependent on various different factors like
1. Dashboard Requirement: Is your requirement finalized? Are all the KPIs captured and given priorities? Are these KPIs communicated and validated by dashboard users?
The requirement phase of any dashboard will take more time as there will be many iterations in finalizing the requirement and prioritizing the KPIs. If you put more time here, it will reduce changes in your dashboard.
2. Data: This is the most important part of your visualization layer. If your data is wrong on your dashboard then your visualization will be wrong and ultimately your business will take wrong decisions.
Before starting the development of dashboards, make sure you have all the required data captured in your eco-system. Also, make sure you check the quality of the data captured. If you are considering data capturing and data quality management in your dashboard estimation, then you should be very careful in estimating this phase.
I will recommend you to create a document of KPIs and divide the KPIs into two sections. 1. The logic implemented in Database 2. Logic Implemented in Tableau
This will help you reduce your iterations in database changes.
3. Paper Design / Prototype:
The design of a dashboard will take comparatively more time as there will be frequent changes/ feedbacks in graph types, colors, alignments, dashboard structure, filter positions and other aesthetic parts of a dashboard. Hence it will always be better to create a paper design of the planned dashboard and get it approved by dashboard users. It will reduce the changes in your dashboard after completing the whole dashboard.
As per my experience, without a paper design, a dashboard will have more iterations once it is presented to dashboard users. That’s mainly because they visualize something else while discussing the KPIs, and the end dashboard doesn’t match with their visualized dashboard. Hence, it’s always better to give them designed dashboard.
4. Dashboard Development:
If you have finalized the paper design and required data, a good developer should not take much time to complete this phase. There are few best practices which can be followed in order to make the development process faster and that will avoid the rework.
5. Dashboard Testing:
Another phase of dashboard development which will take a considerable amount of time. It’s always recommended to put more time and efforts into the testing phase.