Context: Software engineering is a social and collaborative activity. Communicating and sharing knowledge between software developers requires much effort. Hence, the quality of communication plays an important role in influencing project success. To better understand the effect of communication on project success, more in-depth empirical studies investigating this phenomenon are needed.

Objective: We investigate the effect of using a graphical versus textual design description on co-located software design communication.

Method: Therefore, we conducted a family of experiments involving a mix of 240 software engineering students from four universities. We examined how different design representations (i.e., graphical vs. textual) affect the ability to Explain, Understand, Recall, and Actively Communicate knowledge.

Results: We found that the graphical design description is better than the textual in promoting Active Discussion between developers and improving the Recall of design details. Furthermore, compared to its unaltered version, a well-organized and motivated textual design description–that is used for the same amount of time–enhances the recall of design details and increases the amount of active discussions at the cost of reducing the perceived quality of explaining.