A Task Force is an ad hoc Committee of the Board. Task Forces are established to work on a defined task or activity with a stated term of 12 months (with extension possible). Based on the activity or tasks, a Task Force may be extended by a vote of the Board. A Task Force may have multiple projects, tasks or activities.
A Working Group is an ad hoc Committee of the Membership where a collection of members come together to achieve a single, stated objective or project. A working group might involve members from different committees or individual members collaborating on a project. Unlike a Task Force, a Working Group is formed by individual members or committees and does not need a vote of the Board to be established, but does notify the Board of its charge/mission and the intended term (e.g. one year, six months, etc).