Regular readers know we stress the importance of focusing on business requirements when designing dimensional data models to support the data warehouse/business intelligence (DW/BI) environment.
Bob Becker on November 5, 2013
As described in Design Tip #157, it is critical to include business partners in the dimensional design process. But including business representatives on the design team obviously increases the size of the group. In many organizations, the resulting team will be a small group of four to eight individuals. In these situations, managing the design process is relatively straightforward.
The team needs to gather on a regular basis, focus on the effort at hand, and follow a defined process to complete the modeling effort.
However, in larger organizations, especially when the scope includes tackling enterprisewide conformed dimensions, the design team may be considerably larger. In recent years we’ve participated in design projects with over 20 participants representing different departments. Large design teams introduce several additional complications that need to be overcome.
The first obstacle is ensuring the consistent participation of team members in all the design sessions. Everyone involved has normal day-to-day job responsibilities, in addition to their design team involvement. Inevitably participants will face pressing issues outside the design process that require their presence. The larger the group, the more frequently these absences will occur. When an individual misses important deliberations regarding key issues, the team will need to circle back with the individual, revisit the discussion and design options, and then perhaps reconsider earlier decisions. This discourse may be important to the overall design, but it negatively impacts the team’s productivity. Excessive backtracking and rehashing is frustrating and draining to the group.
With large design teams, you should avoid overly aggressive scheduling to ensure the highest level of consistent participation. Don’t schedule full weeks or even full days for design sessions. We suggest limiting design sessions to no more than three days in a week; Tuesday through Thursday seems to work best. Instead of full day sessions, schedule two sessions per day, each two and a half hours in duration. Start the morning session a little later than the normal start time, take a two-hour midday break, and finish before the normal end time. In addition to Mondays and Fridays, this schedule gives participants time at the beginning, middle and end of each day to schedule meetings, deal with email, and other daily responsibilities. Each participant only needs to allocate fifteen hours per week to the design sessions. In exchange, each participant is expected to firmly commit this time to the design team. The goal is full participation in all design sessions resulting in greater overall productivity and minimal backtracking.
When the focus of the design effort is on core conformed dimensions, it is important all the business representatives participate since the goal is enterprise agreement on the key attributes that must be conformed across the organization. However, once the team’s attention turns to specific business processes and the associated fact table designs, it is often possible to excuse some of the business representatives not involved/interested in a particular business process for several design sessions. Remember that any effort to define core conformed dimensions across business processes requires a clear and urgent message from senior management that they expect the effort to produce results. IT by itself cannot “herd the cats through the door.”
Make sure you have clear and visible guidance from senior management before you start the dimension conforming process or you will be wasting your time. Occasionally, gnarly design challenges will arise. Often these issues are relevant or only thoroughly understood by a small group of participants. Trying to work through these very specific issues may be counterproductive for most members of the larger design team. In these situations, it makes more sense to table the discussions during the general design sessions and assign a smaller workgroup to work through the issues and then bring the conclusions/recommendations back to the larger group.
Effective facilitation is often another large design team challenge. Ideally, the lead dimensional data modeler has the required skills to facilitate the group. However, it is sometimes necessary to team a skilled facilitator alongside the dimensional data modeler. In either case, make sure the facilitator and/or modeler possess the key skills required to guide a large team effort:
- Deep knowledge of dimensional data modeling concepts and techniques, including the pros and cons of design alternatives.
- Understanding of the organization’s business processes and the associated business requirements surrounding those processes within the design effort’s scope.
- Self-confidence to appreciate when to remain neutral on an issue and when to push back. Occasionally, the facilitator/modeler needs to take a contrary position to help participants clearly articulate their requirements and concerns.
- Keen listening skills. Some participants will not be well versed in dimensional modeling, yet will be communicating key requirements which they’re unable to express in modeling terms.
- Strong facilitation skills to draw out participants, adequately debate key issues, control wandering discussions, retain focus on the goal, and ultimately, ensure success.
We also suggest that one team member be assigned to documenting the design and outstanding issues during the sessions. In large group designs, the facilitator/modeler is primarily focused on understanding the requirements and translating those requirements into an optimal dimensional model. Their work requires considerable discussion and evaluation of design options. It’s a productivity gain if the facilitator/modeler doesn’t need to slow down the process to capture design decisions.