When given a large dataset it can feel overwhelming. Where to start?
Before you begin to analyse the data, you need to understand your data and then transform it into something you can gain insights from.
1. Know your data
The first step is to know your data. To do this you should sketch out the dataset; identify what in your data is categorical and what is numerical. Consider the columns and rows in your data, are the headers as expected? Identify the data types, missing data and number of records. Considering and noting all these things help you to get a better understanding of what is needed to transform the data.
2. Desired state
Then you need to think about how you want the data to look in your output. Again, sketch it! Start with your categorical fields that you identified earlier as these will determine the level of granularity of your data. Then note your numerical fields. Each field should be in a column. Each row should be a record containing all the values in each data field.
3. Going from knowing your data to the desired state
Now we need to connect step one and step two.
Create a list of each change you think you will need to make to the data. What do you need to clean? Do you need to pivot? Does your data require aggregating or splitting?
4. Build the flow!
Once you have a list of how you want to shape your data to get to your desired state, start implementing your list into Tableau Prep!