Participation versus Contribution: number of responses submitted per user plotted against response contribution per user.

<p>Plots (a) and (b) use the Childhood BMI data, plots (c) and (d) use the EnergyMinder data, and plots (e) and (f) use the Personal Savings data. In plots (a), (c), and (e), real survey data is used. In plots (b), (d), and (f), synthetic data is used.