Guide to Activity Analysis

What Is Activity Analysis?

Activity analysis is a continuous process of measuring and improving the amount of time that craft workers spend on actual construction. This measured time is referred to as tool time, wrench time, or direct work time.

How Is Activity Analysis Different from Work Sampling?

The practice of measuring direct work time originated in 1927 as an industrial engineering technique called the “snap reading method.” It primarily measured the simple ratio between production and delay. By the 1970s the practice had evolved into work sampling, a process primarily involving the measurement of the relative time that craft workers spent in direct, support, and delay activities. Activity analysis is the next evolution of the practice. Primary differences between activity analysis and work sampling include the following:

• Activity analysis includes significantly more detailed observations. Typically, observations are broken down into seven or more categories: direct work, preparatory work, tools and equipment, material handling, waiting, travel, and personal. These categories are monitored for each of the crafts on a jobsite.
• Activity analysis provides more detailed results. The practice of conducting more detailed observations during every work hour of the day and of separating them out by craft provides a more descriptive assessment of how effectively craft workers’ time is being utilized.
• Activity analysis is a continuous improvement process. Activity analysis relies on a continuous process of improvement through observation, identifying areas for improvement, implementation, and reassessment.

Why the Need for an Activity Analysis Guide?

During the summer of 2009, Research Team 252 conducted an extensive set of field studies during which it conducted activity analysis on six industrial construction projects. The results showed that one project experienced significantly higher direct work rates compared to the rest. That project was the only one that was continuously engaged in activity analysis. The level of improvement of the one project compared to the others was so compelling that the companies on some of the other projects are now actively working towards implementing activity analysis.

Unfortunately, no readily available guide describing how to conduct activity analysis has existed until now. To demonstrate the potential of activity analysis, this document describes the team’s experience during these field trials and analyzes the data collected from them. It also explains how to conduct activity analysis.