Campaigns use crowdsourced ideation to address high urgency problems with facilitated prompts; typically near term, clearly scoped problems/opportunities well understood by employees.
The Campaign topic can be either narrow or broad - both tend to work well.
• With narrow Campaigns, make sure to encourage the audience to still think broadly and be creative, despite a relatively focused topic.
• With broad Campaign topics, make sure to give enough of a stimulus (through a thoughtful campaign prompt or through sample ideas) to kick-start the audience's imagination, otherwise we've seen people have a hard time generating ideas.
A clearly compelling business need should be at the center of the Campaign topic so that you a) are making the most of the time and effort spent on Campaigns, and b) can easily motivate your audience to participate.
A crisp and clear challenge statement is critical - often we find the "How might we..." question-type to be a helpful format.
Accessibility and the ability to pursue the challenge statement independently. The Campaign prompt/challenge statement should be accessible to the audience and it should be a challenge or opportunity that multiple individuals or small teams can pursue independently. The objective is to generate lots of ideas at the start ("divergent" ideation, in the language of human-centered design) from multiple different stakeholders that you can compare against each other and investigate in parallel before down-selecting to the initiatives you want to pursue (the "convergent" stage of human-centered design).