Logic model

Logic models are hypothesized descriptions of the chain of causes and effects leading to an outcome of interest (e.g. prevalence of cardiovascular diseases, annual traffic collision, etc). While they can be in a narrative form, logic model usually take form in a graphical depiction of the "if-then" (causal) relationships between the various elements leading to the outcome. However, the logic model is more than the graphical depiction: it is also the theories, scientific evidences, assumptions and beliefs that support it and the various processes behind it.[1][2]

Logic models are used by planners, funders, managers and evaluators of programs and interventions to plan, communicate, implement and evaluate them.[3][2] They are being employed as well by health scientific community to organize and conduct literature reviews such as systematic reviews.[4][5] Domains of application are various, e.g. waste management,[6] poultry inspection,[7] business education,[8] heart disease and stroke prevention.[9] Since they are used in various contexts and for different purposes, their typical components and levels of complexity varies in literature (compare for example the W.K. Kellogg Foundation[10] presentation of logic model, mainly aimed for evaluation, and the numerous types of logic models in the intervention mapping framework[11]). In addition, depending on the purpose of the logic model, elements depicted and the relationships between them is more or less detailed.