Responsibility assignment matrix
A responsibility assignment matrix (RAM), also known as RACI matrix (pron.: //) or linear responsibility chart (LRC), describes the participation by various roles in completing tasks or deliverables for a project or business process. It is especially useful in clarifying roles and responsibilities in cross-functional/departmental projects and processes.
Key responsibility roles 
- Those who do the work to achieve the task. There is at least one role with a participation type of responsible, although others can be delegated to assist in the work required (see also RASCI below for separately identifying those who participate in a supporting role).
- Accountable (also approver or final approving authority)
- The one ultimately answerable for the correct and thorough completion of the deliverable or task, and the one who delegates the work to those responsible.  In other words, an accountable must sign off (approve) on work that responsible provides. There must be only one accountable specified for each task or deliverable.
- Consulted (sometimes counsel)
- Those whose opinions are sought, typically subject matter experts; and with whom there is two-way communication. 
- Those who are kept up-to-date on progress, often only on completion of the task or deliverable; and with whom there is just one-way communication.
Very often the role that is accountable for a task or deliverable may also be responsible for completing it (indicated on the matrix by the task or deliverable having a role accountable for it, but no role responsible for its completion, i.e. it is implied). Outside of this exception, it is generally recommended that each role in the project or process for each task receive, at most, just one of the participation types. Where more than one participation type is shown, this generally implies that participation has not yet been fully resolved, which can impede the value of this technique in clarifying the participation of each role on each task.
Role distinction 
There is a distinction between a role and individually identified people: a role is a descriptor of an associated set of tasks; may be performed by many people; and one person can perform many roles. For example, an organisation may have ten people who can perform the role of project manager, although traditionally each project only has one project manager at any one time; and a person who is able to perform the role of project manager may also be able to perform the role of business analyst and tester.
Matrix format 
The matrix is typically created with a vertical axis (left-hand column) of tasks (e.g., from a work breakdown structure WBS) or deliverables (e.g., from a product breakdown structure PBS), and a horizontal axis (top row) of roles (e.g., from an organizational chart) – as illustrated in the image of an example responsibility assignment (or RACI) matrix.
There are a number of alternatives to the RACI participation types:
- This is an expanded version of the standard RACI, less frequently known as RASIC, breaking the responsible participation into:
- Those responsible for the task, who ensure that it is done as per the approver
- Resources allocated to responsible. Unlike consulted, who may provide input to the task, support help complete the task.
- This is an expanded version of the standard RACI, with two additional participation types:
- Those who approve the verify decision and authorize the product hand-off. It seems to make sense that the signatory should be the party being accountable for its success.
- This is an expanded version, of the standard RACI, also known as RACIO with one additional participation type.
- Out of the loop (or omitted)
- Designating individuals or groups who are specifically not part of the task. Specifying that a resource does not participate can be as beneficial to a task's completion as specifying those who do participate.
- Another version that has been used to centralize decision making, and clarify who can re-open discussions.
- A single driver of overall project like the person steering a car.
- One or more approvers who make most project decisions, and are responsible if it fails.
- Are the worker-bees who are responsible for deliverables; and with whom there is two-way communication.
- Those who are impacted by the project and are provided status and informed of decisions; and with whom there is one-way communication.
- Another variant used clarify the roles of decision making is the RAPID model
- A responsible propels the process to the decision point and recommends the decision.
- A set of Agrees are give the opportunity to veto the decision.
- The Perform role represents the activities subsequent to a decision.
- The Input role provides input to the recommended decision via two-way communication.
- The Decision role is to take the formal decision thus committing the organization to action.
There are also a number of variations to the meaning of RACI participation types:
RACI (alternative scheme) 
- There is an alternative coding, less widely published but used by some practitioners and process mapping software, which modifies the application of the R and A codes of the original scheme. The overall methodology remains the same but this alternative avoids potential confusion of the terms accountable and responsible, which may be understood by management professionals but not always so clearly differentiated by others:
- Those responsible for the performance of the task. There should be exactly one person with this assignment for each task.
- Those who assist completion of the task.
- Those whose opinions are sought; and with whom there is two-way communication.
- Those who are kept up-to-date on progress; and with whom there is one-way communication.
RACI (decisions) 
- This alternative is focused only on documenting who has the authority to make which decisions. May be suitable for use within a small work group.
- Responsible to recommend an answer to the decision.
- Authorized to approve an answer to the decision.
- Those whose opinions are sought; and with whom there is two-way communication.
- Those who are informed after the decision is made; and with whom there is one-way communication.
- A Guide to the Project Management Body of Knowledge (PMBOK Guide). PMI Standards Committee, Project Management Institute. 2010. ISBN 1-933890-66-5.
- Jacka, Mike; Keller, Paulette (2009). Business Process Mapping: Improving Customer Satisfaction. John Wiley and Sons. p. 257. ISBN 0-470-44458-4.
- Cleland, David; Ireland, Lewis (2006). Project management: strategic design and implementation. McGraw-Hill Professional. p. 234. ISBN 0-07-147160-X.
- Margaria, Tiziana (2010). Leveraging Applications of Formal Methods, Verification, and Validation: 4th International Symposium on Leveraging Applications, Isola 2010, Heraklion, Crete, Greece, October 18-21, 2010, Proceedings, Part 1. Springer. p. 492. ISBN 3-642-16557-5.
- Brennan, Kevin (2009). A Guide to the Business Analysis Body of Knowledge (BABOK Guide). International Institute of Business Analysis. p. 29. ISBN 0-9811292-1-8.
- Blokdijk, Gerard (2008). The Service Level Agreement SLA Guide - SLA Book, Templates for Service Level Management and Service Level Agreement Forms. Fast and Easy Way to Write Your SLA. Lulu.com. p. 81. ISBN 1-921523-62-X.
- Smith, Michael (2005). [ Role & Responsibility Charting (RACI)]. Project Management Forum. p. 5.
- Hightower, Rose (2008). Internal controls policies and procedures. John Wiley and Sons. p. 83. ISBN 0-470-28717-9.
- Baker, Dean (2009). Multi-Company Project Management: Maximizing Business Results Through Strategic Collaboration. J. Ross Publishing. p. 58. ISBN 1-60427-035-7.
- Bolman, Lee (2008). Reframing organizations: artistry, choice, and leadership. John Wiley and Sons. p. 112. ISBN 0-7879-8799-9.
- Dickstein, Dennis (2008). No Excuses: A Business Process Approach to Managing Operational Risk. John Wiley and Sons. ISBN 0-470-48110-2.
- Kendrick, Tom (2006). Results without authority: controlling a project when the team doesn't report to you. AMACOM Books, A Division of the American Management Association. p. 106. ISBN 0-8144-7343-1.