A suicide risk assessment (SRA) is used to decide an individual's suicide risk (how likely they are to kill themselves).  This is a very important first step in helping a person who is thinking of killing themselves.  It is best done by a mental health professional, like a counselor.  A good, complete risk assessment can lead to a person getting the treatment and help they need, which can reduce or end suicidal symptoms. 
 
The first part of an SRA is talking to a doctor - or other trained mental health worker - who asks specific questions about what the person is thinking about, how they feel, and what is going on in their life.  (This is called a clinical interview).

The second part of the SRA uses one or more tests that have been proven to measure suicide risk.  These tests are called "scales."  A scale is a way of measuring something.  Some of these scales have been shown to be very reliable, such as the Suicidal Affect-Behavior-Cognition Scale (SABCS)  and the Columbia-Suicide Severity Rating Scale (C-SSRS).

A suicide risk assessment is not always completely right about a person's suicide risk.  Still, usually it gives a risk score that is helpful for making important decisions about what treatment the person needs. 

  
The risk of suicide may change over time.  It may become higher or lower for different reasons.  For example, treatment (like counseling or medicines) may work, making the person feel better, or not work.  Or the person's life may change in good or bad ways (for example, they may get or lose a job, go to a new school, get a boyfriend or girlfriend, or break up with one).

Because the risk of suicide can change over time, the suicide risk assessment has to be done more than once while the person is in treatment. If the person is in the hospital for treatment, it has to be done before they are sent home.

A suicide risk assessment can be important in helping save the life of a suicidal person.  But an article in a journal called Suicide & Life-Threatening Behavior, written in 2012, says that SRAs are often not done, and that many mental health care workers have little or no training in how to do a suicide risk assessment.

Hospitals, doctors, and counselors can be sued for negligible death if a suicidal person goes to them for help, but they never did a suicide risk assessment.  Negligible death means that the hospital, doctor, or counselor did not do something they were supposed to do, and because of that, a person died.

Suicide Risk After Self-Harm 
Recent self-harm can also provide clues to a person's suicide risk.  When a person hurts himself or herself on purpose, this is called self-harm (or self-injury).  For example, important questions to ask might include:
 Asking about the 24-hour period right before the person self-harmed
 What events led up to the self-harm?
 Did the person plan the self-harm?  If they did plan, how much?
 Asking about the self-harm
 How dangerous was the self-harm?  Could it have killed the person?
 What did the patient think would happen after self-harming?  Did they want to die?
 Did the person hide their self-harm to prevent anyone from stopping them?
 Did the person ask for help before or after self-harming?
 What was the person thinking, feeling, and doing when they self-harmed?
 Was the person feeling even more depressed, angry, or upset than usual?
 Was the person drinking alcohol or using drugs when they self-harmed?
If the same events, thoughts, feelings, and other things that led up to the self-harm happen again, the person may be more likely to self-harm again, or to commit suicide.12

Patient's Rights Issues 
When patients ask for help or even harm themselves, they still have rights.  Sometimes, suicide risk assessments can bring up patients' rights issues. They can also create a conflict between the rights of the patient, and the powers of doctors, mental health professionals, and the law.

For example, many state laws in the United States say that a person can be forced to go to the hospital, even if they do not want to go, if a doctor or mental health professional says they are suicidal.  In some states, the person can be physically restrained (for example, tied to a hospital bed) if they try to leave the hospital.  Some states also allow paramedics and doctors to give chemical restraints (medicines to make the person cooperate or be very tired), even if the patient does not want these medicines.

If after a short stay in the hospital (usually 3 business days), the hospital believes the person is still a risk to themselves, they can ask a court for civil commitment.  If a judge agrees, the judge will order the person to stay in the hospital for a much longer time (usually months).  The person has no right to leave the hospital.

This means that in many cases, if a doctor or mental health professional says a person is suicidal, that person can lose:
 Their right to decide whether to go to the hospital
 Their right to decide what kind of medical treatment they want or do not want
 Their right to freedom

In the case of people who may be suicidal, the law sees the powers of doctors and mental health professionals as more important than the rights of the patient.

Other websites
Landmark Study Finds Columbia Suicide Severity Rating Scale Predicts Suicide Attempt
Rating Scale Successfully Predicts Suicide Attempts
Explanations of Laws about Suicide and Hospitalization in Every State

References

Suicide