Muri – Overburden
Muri is waste associated with pushing people, processes and equipment beyond the limits or overburdening. An organization may be enamored of working large numbers of overtime hours, but any benefit for such some at a cost, and this is an example of overburdening.
I once worked at a place in which the employees averaged being at the organization for between 10 – 20 years, and had vacation time commensurate with being within the organization per the company benefits manual. The people that had been with the company that long had more than 4 weeks of vacation, which is 160 hours off of the 2000 hours or total work hours approximates 1840. On top of this time off, the company also offered special days that it gave off to everybody – think Thanksgiving and Christmas for example. Yet when it came to calculate the work the organization could undertake, the organization used 1980 per person to estimate the total amount of time each employee had to dedicate to the company. When it was mentioned that this number of hours was well above what the average hours per year that would account for a seasoned work force with this sort of vacation time, the executive said they worked considerable overtime and expected that the employees did also. This is planning to overburden the employees, and may have sustainability issues. The same is true when we have mandatory overtime for projects that are behind schedule, or working over the holidays. Project schedules based more on hope or desire than facts and historical data or metrics, run the risk of this sort of overburden. When our team does not have suitable tools within the project (using excel to create Gantt charts) making tracking dependencies difficult and time consuming.
A high work load, that is the work demand is much greater than the processes and talent or resources, we run the risk of increased defects or errors that will creep into the process, or out right not executing as to the process expectations, resulting in defects down stream and rework (muda).
We over burden our staff or specific employees when we assign people to tasks when they do not contain the requisite skills for the work without accounting for this missing expertise in the schedule for the project and that can include things like specific training, and on the job learning to get the team member on the way to acquiring this new set of skills. Tools and equipment that are too few or are not adequate for the job likewise over burden the system. Over burdening of the process can lead to sloppy work an cutting corners (based upon experience) in an attempt to get the work completed. Process overburden leads to long queue time for the work. Machines and equipment can be over burdened and in this case we are not saying 100% is the limit, it is actually lower when you include preventative maintenance on the equipment for example. Similarly, when we produce a project schedule that does not account for variation of task, and variation in transitions between process areas, we are scheduling this overburden of the system.
Overburden happens when we have a schedule that is not driven by the work that needs to be done, but by the schedule that indicates what happens at what point in time not considering dependencies. This does not consider the actual flow of the work.