Rachel Hinman offers a three step framework for Design synthesis after gathering lots of data from research:
What we heard and saw
Capture important points from conversations with customers/users on post-its (memoing)
What it means
Use affinity diagramming to cluster related points – identify patterns. Do this collaboratively, discuss with colleagues. Write down the initial insights
Why it matters
Organize the insights by asking "why this matters?" and ultimately capture it as emerging insights that have implications. Formulate the implications so that they become actionable next steps for you or your team. Support the most important insights with stories