When one thinks about intervention models, the firs thing that usually comes to mind is crisis intervention. What I'm going to be addressing here is a general overview of what any standard intervention should look like.
Step 1: Get an overview of the client/s situation. What is the client/s point of view of the problem? What do they believe is causing the problem? What possible solutions have been tried? How did they work? Think of this as information gathering.
Step 2: Assessment. Develop a possible hypothesis. What is making the situation worse? What systems are involved here? How are external and internal forces acting on the situation? This is not set in stone and may change as more information is presented. Assessment is key to intervention, so this should be done very carefully and thoroughly, and updated necessary. Good assessments are culturally competent.
Step 3: Come to a consensus with client on what needs to happen. What goals should be accomplished to work towards resolving the issue?
Step 4: Agree with the client on the client's role and your role in the intervention.
Step 5: Proceed with the intervention! (Example interventions, agreed on in step #3, could be drug and alcohol counseling, finding and applying for subsidized daycare, attending vocational training, etc.)
Step 6: Evaluate! Always evaluate! Evaluation is both for the client and yourself. After the intervention is over you want to know if it had lasting results.
Ambrosino, R., Heffernan, J., Shuttlesworth, G., & Amrosino, R. (2001). Social work and social welfare: An introduction (4th ed.) Belmont: Brooks/Cole.