Three things to do before building your reports in Power BI
You have started learning Power BI, the service is set up, and you have your first request to build a dashboard. As tempting as it may be just to load a data source and start building your first report, it is essential that you take a moment and do the following three things first. If you don’t, you could be setting yourself up for a frustrating and time-consuming debugging phase that could be drastically reduced beforehand.
Talk to the people who are not only requesting the report but also find some of the users. Take a couple of hours to build a document or outline of what is needed. Figure out which fields are being used the most and see if any calculations are being created in Excel repeatedly. Find out if the users want to be able to drill down through specific data points or if you will need a second report for users to drill through for more specific datasets. After you have laid out your best interpretation of what they want, send the document to get their approval, this document will be your minimum viable product. Doing this can save you much time by avoiding feature creep or worse, spending hours on a section of the report that no one ever uses.
Create/Load Theme and template:
Next, find out if your organization has a theme already chosen or if a template is already created for reports. Themes are color formats for every aspect of the report. If your organization already has one created, then that work is already done for you. That way, your report will match the look and feel of your organization and give the user a feeling of continuity as they move through different dashboards and reports. However, if your organization does not have a theme created or chosen, then stick with one of the defaults and do not modify the colors of the report. That way should the organization decide to create a custom theme in the future they will not have to go through each report and dashboard and manually reset the colors of each visualization to default to use the new custom theme.
Clean the Data:
Now that you have the requirements laid out and the defaults set, load your data source. After it has been loaded, make sure that every column has a data-type set. This is especially important of columns that have date, numeric, or address fields. Also, remove any columns that you know that will not be needed as that can drastically reduce the load time of the report.
If you are looking through the data and begin to note a column that requires a data transformation, then you have two choices: fix it in Power BI or fix the source. If this dataset is only going to be used on this one report or the transformation is only valid on this one report then fixing it in Power BI will be the easiest and best method. However, if this dataset is going to be used in multiple reports and the transformation will also be required, then it might be worth the time to fix the original data source and reload the dataset.
While these three steps are not as enjoyable as creating the reports and dashboards, adjusting the visuals and developing DAX formulas, they are non-the-less important, and if you skip them, it can lead to hours of tedious rework in the future.