Most operating companies don’t adequately measure maintenance staff efficiency — and thus are not in a position to optimize productivity and performance. Our experience indicates that many firms could use a more rigorous approach for measuring utilization and identifying where losses occur. Such a method, called a Labor Activity Analysis (LAA), can assist in understanding causes and pinpointing prospective improvements. So, we will look at how to conduct such an analysis and compile data for use in improvement planning.
Background on the purpose of an LAA, which is a proven industrial engineering technique, was provided in a previous article (CP, October 2005, p. 25) about the calculation of labor productivity. That calculation covers all the direct and indirect activities involved in doing work, including the efficiency and quality of the actual work, as well as time required for travel to the site, retrieving material and preparing the work area. It provides a measure of overall productivity that accounts for all potential losses limiting the amount of work performed. These activities fall into three categories:
- Direct utilization — the percent of time craft personnel are performing direct work;
- Direct productivity — the actual units of work completed as a percentage of a standard; and
- Rework — the percentage of work performed that is flawed and must be redone.
Together these three elements define craft productivity as:
Productivity = (Direct Utilization)/(Target Value) × (Direct Productivity) x (100% - Rework)
Of these three elements, direct utilization is the factor most people refer to when discussing efficiency. Direct utilization is an easily understood concept and most people can estimate “wrench time” or “tool in hand” factors, because this only requires a visual assessment of work activity during a snapshot of time.
In contrast, direct productivity and rework are more difficult to determine. Direct productivity requires an assessment of actual direct work against a standard time while rework demands a detailed knowledge of tasks performed a second time and why they were redone. Both of these elements call for specific work order analysis over a relatively long period of time.
So, not surprisingly, due to the ease of deriving an approximation of direct utilization, simplistic estimates usually drive the determination of overall productivity as the other factors are often assumed to be at or near 100%.
A better way
An LAA provides a more accurate view of utilization. It involves the random sampling of work activities and their measurement and classification as either direct, delay or support activities. This type of analysis often yields far different results than those from simple estimates, and can identify potential improvement opportunities that otherwise would be missed.
We can use an LAA to quantify where time is lost, loss categories, and to measure the amount of gain expected from specific improvement initiatives.
Conducting an LAA involves four steps:
Preparation — the definition of the scope of the study area and demographics of the craft personnel in that area; definition of sampling routes and calculation of sample sizes; and training observers;
Observation — the recording process and determining types of work activity;
Data compilation — data entry and summary of observations to facilitate grouping by loss category; and
Analysis and reporting — assessment of results for use in subsequent barrier and gap analyses.
Prior to performing an LAA, you must review site information to develop a plan for execution. Typical preparation activities include:
- Defining the scope or area of the facility to be studied and identifying applicable technician work areas, e.g., production units, shops, stores and planning areas.
- Determining the number and type of personnel involved in maintenance in that area — if the whole plant is to be assessed, then the entire technician workforce is included.
- Establishing routes to be walked by the observers that allow a scan of the entire study area; walking the routes with all observers to familiarize them; ensuring the combined walking routes will consistently cover what all technicians are doing in the area.
- Setting start times for each route and publishing a schedule.
- Deciding upon the degree of accuracy (sample size, number of rounds and shifts, etc.) needed for the study.
- Selecting the method for identifying the maintenance workforce.
- Scheduling orientation sessions with management, supervisors and the workforce.
After defining the study area on a site layout drawing and the applicable maintenance personnel that support the area, the preparation activity focuses on the route planning and scheduling the number of observation routes required for statistical accuracy.
The plan identifies the walking routes to be used by the observers while the schedule documents the number of tours/routes to be taken during the survey. Both need to be developed early in the preparation period because they drive the accuracy of the study and the length of time required.
Additionally, proper planning will ensure that the initial hours of the first day of the survey result in effective observation sets.
Steps involved in the route planning process include:
- Identifying and tracing the routes on a plot plan and pinpointing start/stop points for each route.
- Establishing walking directions for each route, e.g., clockwise or counterclockwise, to allow it to be randomly walked in either direction.
- Determining a schedule of specific start times to begin the route walks during the day.
Typically each route should be able to be walked in less than 45 minutes. To assure statistical validity of the survey, 85% to 100% of the technician population should be observed. Meeting these objectives may require multiple routes. If so, they should be walked simultaneously and, hence, more than one observer will be necessary.