by Jeffrey C Kadlowec, Registered Architect

The vast number of project elements and complex interdependencies between building systems necessitate prioritization of construction activities. The critical path method (CPM) and project evaluation and review technique (PERT) were developed to quantify the importance of project tasks. Schedule-based indexes further investigate the relative importance of tasks to determine probability and the degree of uncertainty [Zarghami 2022]. These include criticality index (CI), significant index (SI), cruciality index (CRI), uncertainty importance measure (UIM), and schedule sensitivity index (SSI) as shown in Table 1.

Table 1. Defining schedule-based indexes [Zarghami 2022].

Utilizing several forms of construction productivity is often necessary since mathematical measurement of construction activities provided by these indexes provide incomplete representation [Zarghami 2022]. The most reliable method can be determined from Table 2 which outlines the strength and weakness of these five schedule-based indexes. Project managers can then make informed and objective decisions. The indexes also rank risks to prioritize efforts and mitigation actions.

Table 2. Strengthens and weakness of indexes [Zarghami 2022].

Productivity remains the main economic driver towards growth and prosperity translating to higher profits, wages and tax revenue. This resulting in better and more affordable goods and services which have an overall societal benefit [Vogl 2014]. Economic performance relies on its constituents with the construction industry accounting for 6-8% of gross domestic product (GDP). Efficiency is the measure of turning capital and labor inputs into productive outputs. Thus improving performance and productivity are at the core of corporate and government agendas. The United States leads in average labor productivity (ALP) followed by France, Germany and United Kingdom.

Though ALP can be used to measure and compare performance, it is limited to a single factor and does not include econometrics. Total factor productivity (TFP) incorporates capital, labor and materials to determine output with the function:

where the output Y is the ‘shift factor’ A is a function of the inputs K for capital, E as labor and M in materials [Crawford 2006]. The Cobb-Douglas production function illustrates these related factors in a multi-axis curve.

Even with modern equipment, methods and procedures, construction is one of the most physically demanding and dangerous industries with research indicating continued decrease in productivity over the past few decades [Gatti 2014]. With this increased pressure to perform, the physiological condition of laborers is a growing concern to ensure their well-being. New tools and techniques must be developed and deployed to improve safety and performance in order to meet current targets and future project goals. Physiological Status Monitors (PSMs) can track various parameters including heart rate, blood pressure, breathing, oxygen saturation, temperature and perspiration to alert workers and construction managers of potentially hazardous conditions.

Construction, building operations, and demolition are major sources of pollution, further increasing demands on industry professionals to improve processes. Numerous methods of analysis and several environmental guidelines were established to measure and promote sustainable design and construction. Environmental performance score (EPS) is a summation of twenty factors for environmental impact, resource utilization, sustainable contribution, public impact, and care of labor [Shen 2004].

Global efforts throughout many facets of the industry seek to minimize resource depletion and environmental degradation while providing healthy interior and exterior conditions.

Labor productivity comprises three sectors: the construction of new buildings and facilities, civil engineering and civil works projects, and the professional maintenance and repair of existing structures [Haugbølle 2018]. During the last 20 years, positive productivity development has only occurred in new construction, with maintenance and repair displaying little growth and civil work suffering instability and decline. The construction industry has always been criticized for low productivity and poor performance. Obvious improvements to overall quality and increased value are readily apparent, though not well quantified or documented.

References
Crawford, Paul & Vogl, Bernard. (2006). Measuring Productivity in the Construction Industry. Building Research & Information. 34(3): 208-219. DOI: 10.1080/09613210600590051.
Gatti, Umberto; Schneider, Suzanne & Migliaccio, Giovanni. (2014). Physiological Condition Monitoring of Construction Workers. Automation in Construction. 44: 227-233. dx.doi.org/10.1016/j.autcon.2014.04.013.
Haugbølle, Kim; Larsen, Jacob & Nielsen, Jørgen. (2018). Construction Productivity Revisited: Towards Measuring Performance of Construction Output. Engineering Construction and Architectural Management. 26(5): 794-803. DOI 10.1108/ECAM03-2018-0094.
Shen, Li-Yin; Lu, Wei-Sheng; Yao, Hong & Wu, De-Hua. (2004). A computer-based scoring method for measuring the environmental performance of construction activities. Automation in Construction. 14: 297-309. doi: 10.1016/j.autcon.2004.08.017.
Vogl, Bernard & Abdel-Wahab, Mohamed. (2014). Measuring the Construction Industry’s Productivity Performance: Critique of International Productivity Comparisons at Industry Level. Journal of Construction Engineering and Management. ISSN 0733-9364/04014085(10)/$25.00.
Zarghami, Seyed. (2022). Prioritizing Construction Activities: Addressing the Flaws of Schedule-Based Indexes. Journal of Construction Engineering and Management. DOI: 10.1061/(ASCE)CO.1943-7862.0002328.