Imagine a flight of stairs leading from the first to the second floor of a house. This flight of stairs represents movement from the least restrictive level of care to the most restricted. Each step up represents a different clinical level of care.
In addiction treatment for example, the first step would be doing things for yourself such as controlling or stopping your own drinking. 
Some people find they simply can not control their use, and thus need more help in the next step -- such as going to AA or to NA. Sometimes even more help is needed to sort out the chaos and problems resulting from using. Individual therapy in outpatient care is a higher step, and usually meets once per week. Beyond this, is a partial hospital program which meets daily for multiple hours per day, multiple days each week. An inpatient detoxification program might be needed for several days or even up to a week in a hospital, in order to stabilize medically due to the damage substance use can do. Some people require an even more structured level of care and enter into a residential treatment. Finally, some people need to live in a facility for a matter of many months, such as in a half way house or a sober house.
Based upon the clinical evaluation, I will make the referral to the appropriate level of care, with a proper placement recommendation. The level of care offered in my private practice consists usually of once per week, outpatient, one hour long therapy.