Value Tree

What are value trees?

RCA-EO uses the value tree methodology to reliably gauge the applicability of Earth observations to USGS and other Federal agency mission objectives. Value trees are hierarchical structures in which top-level objectives, such as delivering societal benefit or accomplishing agency missions, are broken down into lower-level objectives, connected to supporting products, services, and observing systems inputs. The value tree can be envisioned as an upside-down tree: the trunk divides into large branches which further divide into smaller branches, twigs, and finally leaves. For RCA-EO, the “leaves” are Earth observing systems, and the value tree depicts their connection and contribution to accomplishing USGS and other agency missions outlined in their Strategic Plans.

The value tree can be broken into three parts. At the top are stakeholder interests and what users are trying to accomplish. In the middle are the products, services, and models that deliver the value of the Earth observations. At the bottom are the specific Earth observations and measures that form the foundation of this value.

From value tree to impact assessment

The value tree will be used to determine the impact of an observation system to Federal goals and objectives. Once the value tree has been defined, the subject matter experts who produce the products and deliver the services in the middle of the value tree are asked to evaluate the criticality of each input to their product or service and their overall satisfaction with the input. Collecting and quantifying expert judgment based on hundreds to thousands of years of collective staff experience enables a quantitative analysis of very complex and extensive value trees. Using the experts’ scores and decision analysis software, the analysts develop a model of the value tree that can determine a performance score at any node in the tree based on the nodes below it. Once the value tree has been completely scored and modeled, an impact score can be determined for every EO system with respect to the top of the tree or any intermediate node in the tree. Each individual impact score can then be compared to other systems’ impact scores in a portfolio analysis to compare the ability of an EO system to meet agency program objectives.

From value tree to user requirements

The value tree analysis provides a detailed understanding of how current observation capabilities and products support Federal goals and objectives. The value trees also provide a strategic context for identifying basic user Earth observation requirements. The value tree model can also be used to identify where improvements in Earth observing capabilities can be made in a particular area that will produce the most improvement overall to a Federal goal or objective.