Promotion & tenure preparation guidelines vary by college and department and rarely include instructions on how to use impact metrics beyond traditional citation counts and journal impact factors. Yet a small but growing number of universities include altmetrics in their tenure and promotion preparation guidelines.
Clear and objective instructions help candidates provide meaningful information and help reviewers make sense of the numbers. For example, what does it mean if a tenure candidate says he received 5 citations for a paper published in 2013? Whether that's a good or bad number is often dependent upon the average citations that others in the field receive, and also the year the paper was published (as older papers tend to have more citations, by virtue of just being around longer).
Approved Academic Unit Policies are available through the Provost Office: If you are interested in updating promotion and tenure guidelines to better document the use and interpretation of impact metrics, contact your department chair, the Faculty Senate, or the Vice Provost for Faculty Affairs
Some faculty are still unfamiliar with altmetrics, so do your homework before deciding whether or not to include altmetrics in your dossier. Talk to your department chair, mentor, and others in your department who have gone up for promotion and tenure recently.
If you do choose to use altmetrics in your dossier, be selective with the metrics you plan to include. Prioritize the types of scholarly impact and/or public engagement you're looking to highlight, rather than overwhelming your reviewers with all of the numbers.
For example, if you're looking to document your public outreach and engagement initiatives, you can include how often your work has been mentioned in the press and on social media, the pageview statistics for your lab's blog, and the citations your articles have received on Wikipedia. If you want to document the scholarly impacts of your work, you can include the number of citations you've received, how often your work is bookmarked on Mendeley (and by what demographics), reviews of your work by other scholars.