A tool for integrating time, cost and quality perspectives in Probability Impact (P-I) Tables

Abstract

Abstract:One widely documented tool for project risk analysis is the Probability-Impact (P-I) Table, which assesses the probability of occurrence of a risky event and its likely impact on the project objectives, which are typically articulated in terms of cost, time and quality. Whilst there are numerous adaptations of the P-I Table, they are all consistent in treating the project objectives as independent and unrelated variables. This is a major limitation of the tool and reduces the P-I Table's practical applicability, as in most project contexts the probabilities and impacts of a risky event on the project objectives will be inter-related. To address this limitation, this paper presents a new tool that uses vector theory to enable a single calculation of the overall probability and impact, incorporating the perspective of all three objectives. The tool is illustrated through a practical application to a real case construction project.

A Concept Model to Scale the Impact of Safety Risk in a Construction Project Using a Semi Quantitative Method

“…The allocation of project resources has an impact on the cost schedule with a non-linear trend as well. The formulation with a non-linear cardinal scale is in line with the scale found by other researchers for the impacts of cost, quality and time risk using a semi-quantitative scale [3,13]. The safety risk impact parameter model (I) using the semi-quantitative method can be formulated using a scale of 1 to 5 with a brief description of the impact ranging from very low to very high.…”

“…(a) Triple Constraint [7] (b) Diamond Constraint [7] (c) Integration of risk Cost, Time and Quality [13] (d) Integrating the risks of Cost, Time, Quality and Safety (concept proposal)…”

“…The scale of the impact of measurement I with 5 categories 1 -5 was presented in 10 reference sources [3,[12][13][14][15][16][17][18][19][20]. The varying descriptions of the category scale of 1 -5 can be seen in Table 3.…”

“…The safety impact parameter model using the semi-quantitative method obtained from the research results as shown in Table 9 can be used in integrated project risk analysis in relation to cost, quality, time and safety. This is because it is aligned with the risk impact scale model using the semi-quantitative method for the variables of cost, quality and time [3,13]. The semi-quantitative risk impact scale model with the variables of cost, quality and time from the related references and the safety variable obtained from the research results can be seen in Table 10.…”