Using Precursor Analysis to Prevent Low-Frequency High-Impact Events, Including Fatalities

RT-321 Topic Summary
RT 321


The ultimate goal of RT-321 was to create a precursor analysis protocol for construction that enables practitioners to: 
  1. Assess conditions in a leading fashion
  2. Identify the presence, and quantify, of precursors in a structured and methodical fashion
  3. Predict and prevent the potential for a fatal or disabling event
Using a combination of literature review, input from industry experts, empirical data collection, a series of randomized and blinded experiments, and objective multivariate statistical analyses, the team was able to achieve the aforementioned goal. This project yielded the construction industry’s first valid and reliable method for identifying leading conditions that predict high-impact, low-frequency (HILF) events. The implementation resource IR321-2 Guide to implementing precursor analysis in construction provides guidance for identifying conditions that have the potential for severe or fatal injuries based on the concept of energy, identifying the presence of anomalous conditions (precursors) that precede fatal and disabling events via a strategic discussion with a work crew, and correcting deficiencies. 

IR321-2 includes a tool to predict the occurrence of construction fatalities (the precursor analysis protocol and a precursor analysis scorecard). 

Key Findings and Implementation Tools

1 : Three-Step Process

Precursor analysis involves the three-step process shown in the figure below (RS321-1, p. 4).

Step 1:  Identify if high energy is present 
Step 2:  Assess the presence of key precursors 
Step 3:  Release work or stop work to make corrections 
Reference: (RS321-1)

2 : The quantity of energy present in a work operation or condition before an incident occurs is a direct predictor of the severity of an injury.

The research revealed that work involving a magnitude of energy equal to 1,500 ft-lbs or greater has the potential to result in a fatal or disabling injury (RS321-1, p. 8).
Reference: (RS321-1)

3 : Professionals are able to use the precursor analysis protocol developed in this research and their intuition to correctly predict the occurrence of HILF events significantly better than random

Using the precursor analysis process and judgment, experts, moderately experienced professionals, and inexperienced students were able to distinguish between success (no event) and failure (near miss or high-impact event) far better than random (RS321-1, p. 13).
Reference: (RS321-1)

4 : Mathematical models provide a valid, reliable, and objective method for predicting the occurrence of HILF events

Objective predictive models were created using advanced statistical modeling (PCA, GLM, logit transformation). These models were able to distinguish between success and failure for all 10 validation cases, and were used to create the simplified scorecard, which is the subject of IR321-2 (RS321-1, p. 16).
Reference: (RS321-1)

5 : Implementation Tool #1

IR321-2, Guide to Precursor Analysis for Construction Fatalities 

This Implementation Resource includes:

  1. Required foundation of safety management for precursor analysis
  2. Intended users who have the expertise necessary to implement precursor analysis 
  3. When to implement precursor analysis based upon the concept of high energy (> 1,500 ft-lbs)
  4. Precursor analysis protocol involving a series of questions to ask of a crew and observations to make in order to identify precursors  
  5. Precursor analysis scorecard provides a simplified method for identifying when work should be stopped because a high probability of fatal or disabling injury has been identified  
  6. Methods for addressing precursors based upon the expertise of the research team
  7. An example case with actual responses, interpretations of responses, use of the scorecard, prediction, and recommended actions
Reference: (IR321-2)

Key Performance Indicators

Improved safety, Prediction of work with high potential for fatal or disabling injuries because of work site conditions and operations (energy) and anomalous conditions

Research Publications

Precursors of High-Impact, Low-Frequency Events, Including Fatalities - RS321-1

Publication Date: 10/2016 Type: Research Summary Pages: 33 Status: Supporting Product

Guide to Precursor Analysis for Construction Fatalities - IR321-2

Publication Date: 10/2016 Type: Implementation Resource Pages: 34 Status: Tool

Precursor Analysis for the Construction Industry: A Systematic Method for Predicting and Preventing - RR321-11

Publication Date: 10/2016 Type: Research Report Pages: 64 Status: Reference

Presentations from CII Events

Plenary Session - Using Precursor Analysis to Prevent Low-frequency High-impact Events, Including Fatalities

Publication Date: 08/2016 Presenter: Number of Slides: 9 Event Code: AC2016

Implementation Session - Using Precursor Analysis to Prevent Low-frequency High-impact Events, Including Fatalities

Publication Date: 08/2016 Presenter: Number of Slides: 34 Event Code: AC2016