# Integration of Cost and Work Breakdown Structures in the Management of Construction Projects
## 2 Literature Review
### Cbs
#### 2.2.2 Coding Systems in the Construction Industry  
A coding system is a methodology based on relationships and affinities that promotes organization and standardization. Coding systems allow terms homogenization, but also the adoption of common methods and concepts. They must have these three properties [91]:  
* Consistency (single classification principle). * Mutual exclusivity of categories. * Exhaustiveness. Identifying the criteria to be applied in the decomposition of WBS is the first challenge [13]. The International Organisation for Standardisation (ISO) identified eight possible classification criteria of construction information [92]: Space, element, work section, construction product, construction aid, attributes, and management. However, other authors have suggested to separate construction and engineering works [93]. Namely, the latter proposed a construction information classification system on the one hand (based on facility, space, element, operation, and resource criteria), and an engineering information classification system on the other hand (this based on construction type, life cycle, product or service, function, tasks, and man-hour attributes criteria) [54]. Figure 4: Hierarchical structure of Spanish construction price databases. Figure 3: Activity-based costing in the construction industry. Hence, it soon became apparent that these deeply rooted national approaches would make the adoption of an international standard difficult. In this situation, a compromised agreement was necessary. A framework for classification tables was suggested that would at least make communication easy between the classification tables that different national organizations were using. This could spur them on to establish tables using the same criteria. This is why in the second half of the 20 th century, construction organizations from different countries began to develop other classification and coding systems [93]. A good example was the European classification standard Code of Measurement for Cost Planning (CMCP) [94]. This standard is observed in Europe. The CMCP was developed by the European Council of Construction Economists (CEEC), which encompasses the following countries: Belgium, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Hungary, Ireland, the Netherlands, Poland, Portugal, Spain, Switzerland, and United Kingdom (UK). The European system is based on the classification and coding of the German standard DIN 276-1 [95] and, to a lesser extent, on the standards from other countries (BSAB from Sweden [96], UniClass from the UK, Australia and New Zealand [97], TALO from Finland, Estonia and Russia [98], and DBK from Denmark [99], etc.). The CMCP, and its successor ICMS [100], arise from harmonizing working methods and exchange of information among construction projects. This is achieved by sharing a standard set of measurement rules and essential guidance on cost management. According to the CEEC [101], the creation of a WBS for construction projects consists of these six stages:  
1. Identify the final result (or deliverable) to achieve the objectives. 2. Review the scope to ensure consistency between requirements and the WBS elements. 3. Define the chapters (first level of decomposition) in a way that facilitates the understanding by dividing them into clearly differentiated blocks. 4. Continue to break down each chapter to an appropriate level of detail. 5. Break down the chapters to the final level of detail (construction unit), where both the cost and the schedule are reliable, allowing efficient project monitoring and control. 6. Review and refine the WBS until main stakeholders agree on the planning and execution. There have been other coding system initiatives. In United States (USA) and Canada, the Construction Specifications Institute (CSI) [102] created standards such as Masterformat [103] and Uniformat [104]. Masterformat keeps a material-based organization and Uniformat keeps a systems-based organization.