Evaluators read applications in their own individual way. Some go directly to the main body of the text, while others look at the summary and technical description. The summary must therefore be good. Also note that there are very few evaluators that have special knowledge of your segment of the field of study. The summary can therefore also be used to mark out a direction for reading the application itself. In addition, the summary may be used in communication between the evaluators and in the event of a possible grant. It should give the reader mental "hooks" to hang the project on, in order to help remember it.
Summary for H2020 applications
The H2020 application templates (European Commission) specify:
Short summary (max. 2,000 characters, with spaces) to clearly explain:
• the objectives of the proposal
• how they will be achieved
• their relevance to the work programme.
Will be used as the short description of the proposal in the evaluation process and in communications with the programme management committees and other interested parties.
• Do not include any confidential information.
• Use plain typed text, avoiding formulae and other special characters.
This means:
• The summary must mirror the project description
• The project's primary- and subsidiary objectives must be clearly thought out and formulated
• Note that the objective is only about what, not how or why
• Then describes how ("how they will be achieved"), and why ("relevance")
• Remember that the summary can easily be reused in a communication context, e.g. on the project’s web pages
• Note that the summary should be written so that it can be published
Writing Tips
One writing trick is to start with either "[acronym] will [what to do]" or "To [what to achieve], [acronym] will [what to do]." For example, «To reduce the number of road accidents in Europe, Project X will explore, map out and encode the relationship between alpha waves and driving skills».
You could also check with someone from another discipline and/or a communication professional. They may be able to come with good input to make the summary even better. The summary should be understandable even for people from other disciplines.