Data always needs to be transformed to make it useful. Using workflow tools like Tableau Prep, Knime, Alteryx or just Excel, is often necessary to normalize and prepare data for use. Whether creating personalized (VDP) marketing applications or analyzing responses to a survey, data preparation is essential for robust results.
Simple principles like ensuring correct data types (string, integer, date, etc) is critical to ensure meaningful data analysis. Often data can be cleaned, even if not correctly gathered. Poorly designed surveys require additional data cleaning to ensure measures and dimensions are correctly transformed for analysis and visualization.