What is the importance of defined team roles and responsibilities?

Huge importance for sure.

- for measuring/scaling

- for estimation of work done and pending jobs

- for better planning or re-assigning, etc.

- appreciation

My 2 cents. Thanks.

I agree with my friend Gayasuddin answer, and I might add that it's the best way to ensure a better working environment.  

A critical issue that can impede the success of teams is a lack of clarity regarding the roles, responsibilities, and expectations of the various agencies and/or individuals who compose its membership. This exercise is designed to assist team members to understand more fully their own roles and responsibilities in relationship to the work of the team, and to provide them with an opportunity to share their expectations about the roles and responsibilities of others.

Because it can be difficult to understand fully the distinction between a role and a responsibility, please keep the following definitions in mind as you move through this exercise.

• Roles — Generally, roles are the positions team members assume or the parts that they play in a particular operation or process. (For example, a role an individual might assume is that of facilitator, or communications liaison).
• Responsibilities — On the other hand, responsibilities are the specific tasks or duties that members are expected to complete as a function of their roles. They are the specific activities or obligations for which they are held accountable when they assume—or are assigned to—a role on a project or team. (For example, some of the responsibilities of a person in the role of team facilitator might include making sure that meeting agendas reflect feedback and input from all members, that the meetings start on time and end on time, and that all members have opportunities to contribute to discussions.)

Generally speaking, there are two types of roles that team members may have. There are formal roles, which are the essential parts or positions that must be filled in order to collectively accomplish the goals of a project or team, and there are also informal roles, which may or may not be required in order to achieve the team’s goals, but that can have an impact—either positive or negative —on the progress of the team.

When we refer to formal roles, we are describing essentially “who” is responsible for “what.” Formal roles are absolutely essential for the success of the team. Obviously, if individual team members do not know what they are expected to do, it is highly unlikely that anything will get done. Again, a lack of clarity around roles and responsibilities is one of the primary reasons that teams fail to produce results. In addition, it is unlikely that members will continue to be interested or invested in a project if they do not know why they are involved or what is expected of them or the other members.

Unlike formal roles, informal roles are not assigned. Instead, they are assumed by individuals because of their personalities, motivations, individual styles and attitudes, or the ways that they like to approach situations or tasks. Just as it is important to understand or recognize the formal roles people have on a team, it is also critical to identify the informal roles played by individuals, because informal roles can have a significant impact on a team. Certain types of informal roles can enhance the overall productivity of the team, but the impact of other types of informal roles—if not addressed—can be negative and may detract from the team’s ability to function effectively. The following are examples of some of the informal roles that members play on teams.

• Teams might have a caretaker. This is the person who makes sure that there is harmony, that everyone is getting along, and everyone’s needs are being met.
• Sometimes teams have an informal spokesperson. This is the person who takes responsibility for hearing everyone’s voice, synthesizing different opinions, and then speaking out on behalf of the group.
• The role of the comedian is played by the person who wants to assume responsibility for making sure everyone is having a good time. Comedians break tension and conflict with humor. They make sure teams do not take themselves too seriously.
• There is the catalyst. This is the person who is like the cheerleader, who contains the energy for the project, gets people excited, and forces people to move forward.
• The optimist is someone who is always looking at the positive side of issues, who brings an upbeat perspective.
• There is the pessimist, who brings the negative perspective. Pessimists often will call themselves “realists” because their view of reality is negative. But the true realist is not necessarily negative.
• The realist is the person who conducts the reality checks for the team, who wants to see the team succeed and not get blindsided by events that are unanticipated.

These are just some examples of the kinds of informal roles that individuals play. The important thing to note here is that informal roles do have a significant impact—both positive and negative—on the work of teams, and it is important to identify and address those effects when necessary.

As has been emphasized, clear roles and responsibilities are critical to the ultimate success of teams. However, such clarity is not always present within collaborative teams—particularly when teams are first established, and especially if there are individuals on the team who have not worked together previously. Regardless of whether a team is newly formed or longstanding, each of the team members will have desires and beliefs about what the other members of the team could or should be doing. These beliefs are referred to as role expectations, and it is very important for members to discuss them so that there are no misunderstandings between what team members expect of one another or one another’s agencies, and what individual members perceive their own roles to be.

Exercise Purpose

Team members come from different specialties and backgrounds, and it is important that they “step outside” their professional day–to–day responsibilities and think in terms of what they can specifically contribute to the team and how each can positively improve the level of team collaboration.

This exercise allows time to discuss what individual team members believe they contribute to the team. It also provides all team members with an opportunity to comment on how they view other members’ contributions. The purpose is to clarify and agree on each member’s roles and responsibilities on the team.

Exercise Instructions

• Using the attached Role Expectations Worksheet, individually write a brief statement describing your perception of your roles and responsibilities on your team. Give thought to the unique skills, talents, and expertise you bring to the group and how these relate to the specific role(s) you can perform. Your statement should include information about what you think the other team members expect you to contribute.
• Using the attached Role Clarification Worksheet, write brief comments about what you expect each of your teammates (list each by name) to contribute to the team’s operations and performance.
• Read your roles and responsibilities description, and express what you see as your contributions to the team. Allow others to ask questions and clarify your comments. Have others describe their expectations of you. Compare and contrast your personal ideas with those of your fellow team members. Discuss any differences in opinions or observations.
• Follow the instructions above for each team member. Come to an understanding of and consensus on each person’s roles and responsibilities on the team.

agree with mr. Gayasuddin Mohammed  in his answer