2. What do you need to find out?

For managers engaged in evidence-informed planning or practitioners committed to evidence-informed practice, there are three key components to consider when formulating questions about the effectiveness of services:

• Target: Who are your service users?
• Intervention: Which services are you considering introducing, developing or changing?
• Outcome: What do you want to achieve?

Furthermore, you need to decide which of three types of outcome question to use:

• General: You know what the problem is, but have no particular solutions in mind.
• Specific: You know what the problem is and have a solution in mind, but you want to know whether it works or not.
• Comparative: You know what the problem is and have several solutions in mind. You want to know which one will be the most effective.