Logic models
The W.K. Kellogg Foundation Logic Model Development Guide provides a nice overview of the transition from data gathering, through outputs to outcomes and impact.
The Logic Model example provides a neat way to visualise the transition from activity, through outputs and data gathering, to outcomes and impact. Outcomes are the specific changes and consequences evaluated, such as behaviours, knowledge, skills, status, wealth, well-being or effectiveness, to mention a few instances. Impacts are the fundamental changes that occur because the outcomes demonstrate a set of benefits to a defined group in a specific timeframe. Such impacts can be intended or unintended and, most importantly, may be either positive or negative to some or all of the stakeholders.