Table 2 BCTs observed in phase two training, delivery mode and link to components in the COM-B model

4.1 Instruction on how to perform behaviour

Interactive and didactic: Pharmacist facilitator explained in initial slides how to use international units, then participants instructed others during the game.

6.1 Demonstration of behaviour

Interactive: Teams demonstrated their drug calculations to each other.

8.1 Behavioural practice and rehearsal

Interactive: During the game, repeated practice in calculating drug doses.

12.5 Adding objects to the environment

The partnership provided calculators, pens and notepads to participants and encouraged their use to calculate accurately and show their workings.

1.1 Goal setting and 1.4 Action planning

Interactive: Time was allocated for participants to set goals and make a specific action plan about where and when they would use their calculator.

1.2 Problem Solving

Interactive: Whole group discussion on difficulties distinguishing long and short-acting insulin and strategies to help, supported by lead nurse.

5.1 Information about health consequences

Didactic: FJD highlighted some health consequences of medication errors.

9.1 Credible source

As in phase one, the facilitator was a senior pharmacist in the hospital and therefore a persuasive and perhaps motivating source about medication safety.

13.2 Framing/reframing

Interactive: Large group discussion, lively debate and team working in the game may encourage a new perspective, that it is acceptable to ask nursing and pharmacy colleagues for help in drug calculations.

1.6 Discrepancy between current behaviour and goal

Didactic: Though a series of whole group questions, pharmacist jokingly pointed out a discrepancy between participants’ perceived and actual competence, highlighting the need to engage in the training.

1.9 Commitment

Interactive: The health psychologists asked participants to share their action plan with a neighbour, to promote commitment to accurate drug calculation.

2.2 Feedback on behaviour

Didactic + Interactive: The pharmacist facilitator included local audit data to PowerPoint slides as hospital-level feedback on drug calculation errors and outcomes. Also in the game, participants fed back to each other whether their drug calculations were correct.