What metrics are used to measure success in treating dysthymia? What metrics are used to measure success in treating dysthymia? 

What data is available on the outcomes of dysthymic patients?
The measures of dysthymia are similar to that for major depression. Dysthymia is not as acute as major depression and one of the key indicators for diagnosis is that it is persistent.

Dysthymia is a chronic type of depression in which a person's moods are regularly low. However, symptoms are not as severe as with major depression.
The main symptom of dysthymia is a low, dark, or sad mood on most days
for at least 2 years. In children and adolescents, the mood can be
irritable instead of depressed and lasts for at least 1 year.
In addition, two or more of the following symptoms will be present
almost all of the time that a person has dysthymia:
Feelings of hopelessness Too little or too much sleep Low energy or
fatigue Low self-esteem Poor appetite or overeating Poor concentration
People with dysthymia will often take a negative or discouraging view
of themselves, their future, other people, and life events. Problems
often seem more difficult to solve.

Much of the treatment involves good mental and physical health practices. Exercise, diet sleep, taking up hobbies, having a balance between work and play.
Professional therapy my also assist, in helping the individual to work through underlying causes of unhappiness, such as destructive behavioural patterns, unresolved conflicts, etc.
SSRIs have proven to be an effective treatment for dysthymia. It should be noted that the standard treatment for dysthymia is considerably longer than for major depression. This could be because of the fact it is a debilitating, long term condition.

The treatment of dysthymia with medication:
When antidepressants are prescribed for dysthymia, the treatment lasts for up to five (5) years (range: 2 to 5 years). This is much longer than the treatment time for major depression (range: 6 to 18 months). Until the availability of the SSRI (selective serotonin reuptake inhibitor) medications, it was difficult to keep a dysthymic person on medication for the several years needed to treat the condition. SSRIs have fewer side effects than the older types of medications for depression, namely the MAOI (monoamine oxidase inhibitor) medications and the TCA (tricyclic antidepressant) medications.