Credential holders may earn PDUs towards the maintenance of their credential through formal academic courses or courses offered by a provider (R.E.P. or Component). However, these are only two of the five categories of PDU earning opportunities in which a credential holder may participate. The other categories of PDU earning opportunities include self-directed learning, volunteering, authoring and other types of project management experience. CCRS uses the term “activities” to describe all courses or events for which a credential holder may complete to earn PDUs.