Table 2 Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) diagram illustrating the design and timescales of the IGLOo cluster-RCT pilot

 Organisation recruitment

x

 Eligibility Screen

x

 Organisation informed consent

x

 Allocation

x

 Manager informed consent

x

 Worker informed consent

x

 Leader e-learning (P1)

x

 Worker and manager toolkits (P2&3)

x

x

x

x

x

 Worker telephone coaching

x

x

x

 Control group—usual practice

x

x

x

x

x

 Organisational sickness policy

x

 Organisational sickness report data

x

 Feasibility outcomes (recruitment)

x

 Feasibility outcomes (retention, compliance)

x

x

 Process evaluation

x

x

x

x

x

x

x

 Intervention resource used

x

 Economic evaluation

x

x

x

x

x

x

x

 Organisation-wide survey

x

x

 Timepoint

Baseline

1 month

 Sick leave and RTW policy and practice

x

 Intervention readiness

x

x

 Autonomy

x

 Demands

x

 Communication about mental health resources

x

x

 Demographics

x

 Intervention acceptability

x

 Intentions to apply learning

x

 Transfer of learning

x

 Intention to take part in phase 2

x

 Integration of intervention

x

 Demographics

x

 Days off sick

x

x**

x**

x**

x**

 Mental health

x

x

x

x

x

 Quality of life

x

x

x

x

x

 Healthcare resource used

x

x

x

x

x

 RTW self-efficacy

x

x

x

x

x

 Workplace support and communication

x

x

x

x

x

 Work adjustments

x

x

x

x

x

 Readiness to stay at work

x*

x*

x*

x*

 Job autonomy

x*

x*

x*

x*

 Job crafting

x*

x*

x*

x*

 Job satisfaction and intention to quit

x*

x*

x*

x*

 Demographics

x

 Mental health management experience

x

 RTW management experience

x

x

 Work adjustments

x*

x*

x*

x*

 Work demands

x

x

 Autonomy

x

x

 Confidence managing sick leave and RTW

x

x

x

x

x

 RTW competency

x*

x*

x*

x*

 RTW competency (post- RTW)

x**

x**

x**

x**