II Key elements of logic models
III Functions and benefits of logic models
--Submitted by Samiya Abdi, Health Promotion Consultant – Health Promotion Capacity Building, Public Health Ontario
Public health practitioners strive to consistently deliver high quality, results based programs within the constraints of limited time and resources. As such it is important for them to be equipped with the appropriate tools and resources to plan, implement and evaluate effective programs and initiatives. Planning is a method of outlining the sequence of events that lead to achieving a desired result. It consists of a series of decisions at multiple time points based on information gathered and analyzed.  Evaluation is a process of collecting, analysing and reporting on program data to facilitate decision making and to measure success.  Therefore both planning and evaluation take a systematic and orderly approach to collecting and using data in decision making. A management tool that can effectively and efficiently facilitate program planning and evaluation processes is a logic model. 
A logic model is a pictorial illustration of program resources, activities, outputs and outcomes. [4-6] It provides the practitioner with an opportunity to clarify the purpose of the program, resources that are available to them, actions they are able to take and results they aim to achieve. [5,6] It supports the creation of a road map that outlines various program activities, and products that lead to the intended outcome. It can be used to facilitate thinking and communicating about the necessary steps to take in order to accomplish agreed upon program outcomes. 
II Key elements of logic models
Although the design of a logic model may vary from one to the other, there are six essential components that are common amongst most logic models: goal, inputs, activities, audience, outputs and outcomes. [3-7] The goal, also known as the purpose, outlines the ultimate results a program needs to achieve. The inputs are resources that are necessary to run the program; these include staff, time, research, technology, funding and other necessary elements for the program.  Activities are the actions that are performed within the program using the available resources. The audience are the intended participants that the program targets; a program can target multiple audiences that are effected by the program at varying degrees.
Program outputs are measurable products or services that result from the activities; they are usually quantified in numbers or percentages. The changes that occur as a result of the program are called the outcomes. These changes could be at the individual, organizational, community or system levels. Outcomes are categorized as short, medium term and long term. A long term outcome is the desired result that a program was designed to achieve. Meanwhile short and medium term outcomes are immediate and intermediate results that lead to the ultimate long term outcome for the program. [3-7]
In addition to these six components there may be other components that appear in some logic models: situation, assumptions and external factors. The situation or the context outlines the current status as well as the main issue or problem that the program is tackling. Assumptions are the underlying beliefs on how and why a program should work in a particular way. Assumptions also layout perceived conditions for program success. Another component that is included in some logic models is external factors. These are factors beyond the control of the program which may include political, social and environmental conditions that could influence the program outcomes. 
III Functions and benefits of logic models
There are numerous benefits to be had when using logic models. For one, a logic model simplifies complex relationships between the various components of a program, and is usually shown in a linear fashion for simplicity, logical flow and ease of understanding. [4,7] However, logic models can be presented in a creative and visually stimulating design that showcase the cyclical nature of program planning, delivery and evaluation.  The design selected for a logic model is dependent on the complexity of the program; the intended audience and use of that particular logic model. [4, 5]
As well, logic models provide an accurate and complete reflection of the program in a succinct manner and can assist in determining the most effective pathway for a program to achieve the desired results. [4,7] Also, they can help manage stakeholder expectations through clarifying assumptions and underlying beliefs and values about the what, why, where, how and whom of program planning.  Without this step of examining assumptions there is a possibility of various stakeholders holding different even conflicting views on how a program should proceed; the use of logic models can help to avoid this.
A logic model is usually written in an ‘If’ ‘then statement’; for example if ‘A’ is done then ‘B’ occurs. At times reversed logic is used to map out the components of a program; therefore it might begin with the end or final outcome in mind and work back to arrive at activities that will lead to that outcome. For example if ‘B’ is desired then ‘A’ must occur. This logical thinking clarifies the directional relationship between program components. It critically examines the foundational theory of change for a program; it also creates a shared understanding of the purpose, intended outcome and how various components fit into each other. Simply put, a logic model visually showcases the linkage between various elements of a program from inception to conclusion making it easier to conceive it in its entirety; a key benefit. [4,5]
A logic model can be introduced during any stage of the program cycle. It is a beneficial tool during the program planning, implementation or evaluation stages. As such, the ideal time to create a logic model is during the early stages of planning, as it sets the program foundations, clarifies goals and objectives, outlines planned activities and intended outcomes. It provides an opportunity to assess the current situation and context for program planning and influences decisions around program inputs and expected outputs. [4,7] Furthermore a logic model can be used to build consensus shaping strategies and for setting priorities. It can help lay out program approaches to stakeholders and can also be used to negotiate resources, roles and responsibilities amongst stakeholders. [5,7]
During implementation a logic model could be used as a management tool that ensures that the program is proceeding as planned providing a chance for testing and validation as well as continuous learning and improvement. 
Because a logic model provides synopsis of the overall program it could be utilized as a communication tool. Logic models set the stage for developing evaluation questions and provide a lens to examine program strengths and weaknesses. It can support categorizing and rationalizing program elements. [4,5] Also, when evaluating a program, a logic model helps evaluators to understand a program and provides guidance around what type of evaluation to conduct; how to determine the evaluation questions; and what measures or indicators to use to identify program success. [5-7]
Last, a logic model can be useful as an advocacy tool to gather support or funding for an initiative because it clearly demonstrates how a program should work and why it is needed. It also helps justify the resources required for program success. [5,7]
Logic models can be used to plan a simple activity to complex initiative or policy; it can be as broad or detailed as required.  It is a coherent, succinct communication tool that outlines how a program should work and what results it should achieve. In the program planning stage it creates a consultative process that supports the development of a shared understanding. During implementation it could be used as a performance management tool to ensure program activities are unfolding as planned. [4,5] When conducting an evaluation a logic model supports the creation of an evaluation plan and can be used as a tool to measure success. 
Overall, a logic model reflects the logical flow of program inputs and the activities that link to the generation of outputs that lead to the desired outcomes. It also allows practitioners to bring together various stakeholders, align goals and values as well as identify resources and strategies. It provides a single point of reference to assess implementation and demonstrate success. It is a flexible, responsive collective tool that allows iterative program planning, implementation and evaluation.
Health Promotion Capacity Building Resources
At a Glance: The six steps to planning a health promotion program http://www.publichealthontario.ca/en/eRepository/Six_steps_planning_heal...
At a Glance: The ten steps for conducting an evaluation http://www.publichealthontario.ca/en/eRepository/At_A_Glance_Evaluation_...
Evaluating Health Promotion Programs: Introductory Workbook
Planning and Evaluating Health Promotion Programs: Audio Presentation Series http://www.publichealthontario.ca/en/LearningAndDevelopment/OnlineLearni...
Planning Health Promotion Programs: Introductory Workbook http://www.publichealthontario.ca/en/eRepository/Planning_health_promoti...
Webinar: Logic models–theory to practice http://www.publichealthontario.ca/en/LearningAndDevelopment/EventPresent...
WK Kellogg Foundation: Logic model development guide
Taylor-Powell E, Jones L, Henert E. Enhancing program performance with logic models.
Community Tool Box: Chapter 2 Other models for promoting community health and development. http://ctb.ku.edu/en/table-of-contents/overview/models-for-community-hea...
Center for Theory of Change
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2. Ministry of Health and Long-Term Care. Ontario public health standards 2008. Toronto, ON: Queen's Printer for Ontario; 2014. Available from: http://www.health.gov.on.ca/en/pro/programs/publichealth/oph_standards/d...
3. Taylor-Powell, E, Jones L, Henert E. Enhancing program performance with logic models. Wisconsin: University of Wisconsin-Extension; 2003 [cited 2016 Nov 16]. Available from http://www.uwex.edu/ces/pdande/evaluation/pdf/lmcourseall.pdf
4. Knowlton WL, Philips CC. The logic model guidebook: better strategies for great results. 2nd ed. Thousand Oaks, CA: Sage Publications; 2013.
5. WK Kellogg Foundation. Logic model development guide [Internet]. Detroit, MI: W.K. Kellogg Foundation; 2006 [cited 2016 Nov 16]. Available from: http://www.wkkf.org/resource-directory/resource/2006/02/wk-kellogg-found...
6. Centers for Disease Control and Prevention. Developing an effective evaluation plan: setting the course for effective program evaluation. Atlanta, GA: Centers for Disease Control and Prevention; 2011. Available from http://www.cdc.gov/obesity/downloads/cdc-evaluation-workbook-508.pdf
7. Work Group for Community Health and Development. Community tool box. Chapter 2. Other models for promoting community health and development [Internet]. Lawrence, KS: University of Kansas; c2015 [cited 2016 Nov 16]. Available from: http://ctb.ku.edu/en/table-of-contents/overview/models-for-community-hea...