Document Detail

Title: RR143-11 - Determinants of Jobsite Productivity
Publication Date: 1/1/2001
Product Type: Research Report
Status: Reference
Pages: 187
Diekmann, Heinz, Univ. of Colorado-Boulder
Order Now  

Abstract

This study evaluates the effectiveness of strategies used to improve labor productivity on construction projects. Specifically, we will investigate the impacts early design, early material delivery, and extra construction equipment have on craft productivity. We call this strategy the buffer strategy. This research seeks to determine whether and to what extent relatively larger stockpiles (buffers) of these three essential resources lead to improved productivity. An alternate approach to supplying sufficient physical resources for construction tasks is to spend additional effort in logistics and planning activities to insure that appropriate resources are delivered to the workers. This strategy, which we call the production planning strategy, suggests that instead of large stockpiles of materials, one carefully plans and delivers only the correct resources. Conceptually, production planning offsets its higher planning and logistics costs by avoiding double handling, interest, and waste costs that are associated with providing large stockpiles. Therefore, this study also investigates the effect of changes in non-manual construction planning and operations support personnel on labor productivity. Finally, this study investigates whether it is more cost effective to provide workers with the resources they need for productive work by using the buffer strategy or by using the production planning strategy.

We collected data from piping and electrical crafts on projects that were currently active within the team members’ companies. Data were collected three times over the duration of each craft’s construction schedule. Our results are based on data from 26 process plant projects covering more than 1307 crew days of work. When project curcumstances allowed, data were collected from up to six different crews (three piping and three electrical) during each data collection event. Roughly 62% of the data were from piping crews and 38% were from electrical crews.

The research arrived at interesting and, to some extent, unexpected results:

  1. Additional piping production-related resources, whether materials, design, or construction equipment, resulted in improved piping craft productivity.
  2. Increased resource availability for piping work produced not only better productivity, but also more predictable and stable crew performance.
  3. Additional electrical production resources did not generally improve electrical craft productivity.
  4. Likewise, increases in electrical production resources did not stabilize crew productivity as with piping activities.
  5. For both piping and electrical activities, increased levels of planning and crew support resources led to consistent and significant improvements in craft productivity.

 

Regarding the economic ramifications of our findings, we discovered:

  1. The cost of providing design, materials, and equipment buffers is higher than the labor savings they enable.
  2. Small buffer projects reduce wastes in projects by decreasing project schedules and material storage (time, size, waste, and staffing).
  3. Increased planning support (production management) costs less than the savings it enables.

 

In addition to the “hard” findings of our effort, we observed several innovative methods for improving jobsite performance. In particular, we observed changes to the supply chain and the production management activities on the jobsite. Many of these innovative practices have common features with so-called lean or agile manufacturing methods. Despite the incidental nature of our observations regarding the lean philosophy, its promise, as evidenced by the significant achievements of U.S. manufacturing, convinces us that additional work on adopting lean to construction is justified.