Table 2 Key design principles used to format the intervention specification manual

Clarity

• Specific information about what to do, when and how.

• Effective language including active verbs that specify a recommended action by whom, when, under what conditions, and with what level of obligation (must, should, may ….)

• Avoid ambiguity when a term is vague or can be interpreted in more than one way (e.g. frequently, periodically)

• Direct writing style and active voice

• Proper punctuation with short sentences

• Minimise abbreviations, hyphenations, jargon

• Capture main idea with first few words so readers can skim text easily

• Keep units of meaning together, using bulleted lists to deal with repetition or complex paragraph structures

Persuasiveness

• Crisp and persuasive messages.

• Frame recommendations as ‘gain’ rather than ‘loss’

• Focus on errors of omission (not doing the right thing) rather than commission (doing the wrong thing).

Format – Multiple versions of documents

• Multiple formats or alternate versions can influence accessibility and ease of use. Provide one page summaries.

• Tailor guidelines to their intended end-users. Integrated into the way they do things.

• Present them in ways that can be read and understood

Format – Components

• Key features that have most significance should be highlighted and differentiated from other recommendations

• Use short summaries and algorithms. Flowcharts can describe stepwise recommendations for care, mimicking a real patient encounter.

• Present most pertinent information concisely

• Present information in an expected and logical order

• Mimic familiar documents such as care plans or policy documents etc.

• Don’t mix positive and negative instructions

Format – Layout

• Pictures on left and text on right

• Use information visualisation through graphics and information display (e.g. tables, algorithms, pictures) and information context (framing, vividness, depth of field)

• Left justification enables natural reading. Avoid italics or all upper-case text. 12 point font at least.

• Bundling. Three bundles of three items easier to remember than nine items

• Words used for procedural information and abstract concepts. Images used for special information, and detail. Tables can improve information clarity.

• Colour – use primary colours

• Strong contrast with background

• Use distinctive visual characteristics for different elements

• Purposeful use of highlighting, colour coding, boxes and bullets.

• Colour code related graphics and text.