What is a logic model?

View a brief video guide to Logic Models

A logic model is a visualisation of how a service or programme works, detailing the resources and activities that are needed to make it happen and what is expected as a result. It aids evaluation by identifying the steps of implementation that need to be evidenced and what outputs and outcomes are expected to be seen. This can help to identify data that needs collecting and evaluation questions that are helpful to ask. 

This example logic model was used in the planning and evaluation of the HAPPY perinatal parenting project delivered as part of Better Start Bradford.

Why do I need a logic model?

Logic models help with understanding and explaining the structure and aims of a service and they underpin all robust evaluations of services. You will need a logic model to complete a process flow, develop an evaluation plan, establish data requirements and for any evaluation completed to be robust. 

The elements of a logic model

Need

This details the problem that you are trying to solve through your service. It should draw from the work done during the selection of the service and information gathered in any needs assessment and/or community readiness work. If available, it should include estimates of the numbers or proportion of people/families in need. Eg., poor family nutrition; pregnant women with mild depression, less than half of mothers are breastfeeding when their baby reaches 6-8 weeks.

Inputs

These are the solid or quantifiable things needed to run the service. Eg., money, staff, spaces, physical resources.

Activities

What is actually done with those inputs? Eg., number of sessions run per quarter, guidance written, visits take that place, language assessments completed, staff training delivered. 

Outputs

What has changed due to the activities? Eg., number of families who have a personalised support plan, number of referrals to speech and language support, specific new knowledge amongst staff groups. 

Outcomes

What does the change mean to groups and individuals? Eg., increase in the number of families singing and reading with their pre-school children, improved ability to identify language delay and make appropriate referrals amongst staff groups. 

Impact

The more global results of all that has been detailed in the logic model. Eg., more children achieving expected language milestones at entrance to reception. 

How to produce a logic model

If you are using a model for your service that has been adopted from elsewhere then there may be an existing logic model that can be adapted with specifics for your setting and circumstances. It may be a quick process. 

• Logic models have a standard structure which means you can download and use the same template for every service. If it is particularly relevant to your service, you may want to further separate ‘outcomes’ into ‘short term outcomes’ and ‘long term outcomes’ but this is not necessary for every service. 
• Include in your logic model development, a service manager, someone with a view of the finance, and someone involved in the evaluation. You may feel there are other people who may be useful to include and whom you may have involved in your service selection and/or community readiness processes. 
• Fill in the needs you have identified in earlier work and then work backwards from the impact you want to have, through the outcomes that must be achieved for that to happen, and the outputs that would feed into those outcomes, and so on all the way back to the original needs that you are trying to address.

In doing this be attentive to the following:

• Be as specific as possible: i.e. numbers of sessions, job titles, amounts of money, measurable changes in behaviour/wellbeing etc 
• Be aware that these are connected sections – the inputs are what is required to do the outputs, the outcomes are what changes as a result of the outputs. If any item on the logic model is not connected to what comes before it then it is not logical 
• Multiple inputs and/or activities may be necessary for just a few outputs and only one or two outcomes and impacts so connecting things together does not mean one-to-one matching up