Lagging metrics report what has been achieved by measuring the outcomes or results of past actions or activities. They are easy to measure but difficult to influence. They are useful for evaluating performance and validating hypotheses. Leading metrics predict what is likely to happen in the future by measuring the inputs or drivers of future outcomes or results. They are difficult to measure but easy to influence. They are useful for forecasting and influencing performance. Reference: ITIL 4 Leader: Digital and IT Strategy, page 83-84