Accuracy Required of the Data

The required level of data accuracy for the project depends on the use of the final results and the intended audience. (Will the results be used to support decision making in an internal process? In a public forum?) For example, if the intent is to use the results in a public forum to support product/process selection to a local community or regulator, then estimated data or best engineering judgment may not be accurate enough to justify basing policy decisions on them. In contrast, if the LCA is for internal decision‐making purposes only, then estimates and best engineering judgment may be applied more frequently. This may reduce the overall cost and time required to perform the LCA, as well as enable completion of the study in the absence of precise, first‐hand data. The criticality of the decision to be made and the amount of money at stake also come into play in determining the required level of data accuracy.

Ground Rules for Performing the Work

Prior to moving on to the inventory analysis phase it is important to define some of the logistical procedures for the project.

1. Documenting assumptions – All assumptions or decisions made throughout the entire project must be reported alongside the final results of the LCA project. If assumptions are omitted, the final results may be taken out of context or easily misinterpreted. As the LCA process advances from phase to phase, additional assumptions and limitations to the scope may be necessary to accomplish the project with the available resources.
2. Quality assurance procedures – Quality assurance procedures are important to ensure that the goal and purpose for performing the LCA will be met at the conclusion of the project. The level of quality assurance procedures employed for the project depends on the available time and resources and how the results will be used. If the results are to be used in a public forum, a formal review process is recommended. Evaluators might include internal and external LCA experts and interested parties whose support of the final results is sought. If the results are to be used for internal decision‐making purposes only, then an internal reviewer who is familiar with LCA practices and is not associated with the LCA study may effectively meet the quality assurance goals. A formal statement from each reviewer documenting his or her assessment of each phase of the LCA process should be included with the final project report.
3. Reporting requirements – To ensure that the LCA meets appropriate expectations, participants should know from the outset how the final results are to be documented and exactly what is to be included in the final report. When reporting the final results, or results of a particular LCA phase, it is important to thoroughly describe the methodology used in the analysis. The report should explicitly define the systems analyzed and the boundaries that were set. The basis for comparison among systems and all assumptions made in performing the work should be clearly explained. The presentation of results should be consistent with the purpose of the study. The results should not be oversimplified solely for the purposes of presentation.