The 90% Rule

© 2013 By Bill Eddy, LCSW, Esq.

From my experience as a lawyer, mediator and therapist – as well as reading a lot of research – I believe that at least 10% of the general population has “high-conflict” personalities. This means that they have a repeated pattern of negative behavior which increases rather than reduces conflict and includes:

• A preoccupation with blaming others

• Lots of all-or-nothing thinking

• Unmanaged emotions (many, but not all, HCPs)

• Extreme behaviors

If you meet and get to know someone with this pattern, you can generally predict that they will act with similar extreme behaviors in the future – especially in close relationships. With this in mind, you would generally want to avoid getting too close to such high-conflict people (HCPs).

Yet many people are very surprised when they find out that someone they loved, worked with, were neighbors with, voted for, etc., has a high-conflict personality. This realization typically comes like a lightning bolt from out of the blue. Suddenly, their world is turned upside down as the HCP’s negative behavior becomes the focus of the relationship – which may include fear of public embarrassment, disruption of your relationships with friends and family, alienation from your children, loss of a job or clients, rumors spread, domestic violence and even death.

Is there a way to spot a potential HCP right from one negative incident, instead of taking time to identify a high-conflict pattern of behavior? This could be helpful in terms of forming love relationships, as well as in hiring people at work and even electing people as representatives in government.

In Close Relationships

While it may take a while to discover the above patterns of thinking, feeling and behaving – because it takes time to get to know someone – a simple short-cut to avoid a potentially high-conflict person is to ask yourself if some negative behavior that they have done would NEVER be done by 90% of people.

For example, in his excellent book The Gift of Fear, the author Gavin de Becker described a woman who was seeking a restraining order against her husband. The reason she wanted the restraining order was that he had held a gun to her head. Yet she stated that she would go back to him if he simply promised never to do it again. The police officer she spoke with suggested that her husband would do it again – and the next time would likely be fatal. With that officer’s feedback, she decided not to return to him and years later thanked the officer for saving her life.

Why did the police officer know this pattern and the woman did not? Professionals who see a lot of the same types of cases know what the likely patterns of behavior are and how to avoid extreme behavior. Police deal a lot with violent behavior and many of them know what domestic violence cases look like – even from just one behavior. In this case, holding a gun to her head indicated that he had a dangerous pattern which was likely to continue to its logical conclusion: her death.

On the other hand, the woman was not experienced with these patterns and apparently accepted on faith that her husband’s behavior could be stopped through logic and promises. The incident with the gun was probably something she thought was an exceptional behavior, would not happen again and was probably because he was under stress from some part of his life.

Yet if she applied the “90% Rule,” she may have realized that 90% of people would NEVER hold a gun to their spouse’s head for any reason, regardless of how much stress they were under. This is exceptional behavior which on its face indicates that there is a pattern of extreme behavior.

In Politics and the Workplace

The following example applies in the workplace and in politics. In 2013, Mayor Bob Filner in San Diego received international notoriety for his bullying behavior and especially for his sexual harassment of women – even women in powerful positions. Just several months after he was elected, he was pushed out of office by a groundswell against him.

Was there any way for voters to have known that this might happen? Was there something in his known history? Yes!

Six years earlier, in 2007, he had a well-publicized incident at Dulles Airport outside of Washington DC. He had a complaint about lost luggage and barged ahead of a long line into an area where a customer service representative said he could not go. He pushed her aside and appeared in a rage – which shocked and disturbed the woman and others around them. Charges of assault and battery were made against him, but he was able to simply pay a $100 fine and apologize to her.

Of course, this well-known incident was excused by some because he had been stressed and tired from his frequent travels. But if you apply the “90% Rule,” you should suspect simply from that one incident that there is a high-conflict pattern of behavior because 90% of people would NEVER cut to the head of the line and shove an employee aside to get to their bag – no matter how stressed or tired they were. When his term as Mayor crashed, it was for exactly this type of verbal and physical aggression against women. At least 17 women eventually came forward complaining of sexual harassment. If voters had taken the 90% Rule into account, they could have predicted from this well-known incident that there would be trouble ahead.

In Family Court

I am familiar with a divorce case in which the mother of three children disappeared after the divorce and stayed out of contact with the father for over a year. She then showed up in the same city and initiated regular contact between the children and the father. However, it didn’t go exactly as she wanted it to, and they ended up in family court fighting over custody. The judge said she was interfering with the father’s contact with the children and, therefore, changed custody from primarily with mother to equal time with father – with the admonishment that if she continued to interfere with the father’s relationship with the children that the court would give the father primary physical custody.

As happens with patterns of behavior, the mother did continue to interfere with the father’s parenting time and a hearing was scheduled at which it was possible that the father would gain primary custody. In a repeat of her other high-conflict behavior, she disappeared with the children a day or two before the hearing. While this was a shock to some, it should not have been. Applying the 90% Rule, 90% of parents in family court – even those with high-conflict divorce cases – would NEVER disappear with the children in violation of court orders. She had already done that once a year or two earlier, so it should have been very predictable that this would occur again. A couple years later, she was found and the father was given custody.

In another case I am familiar with, that of Josh Powell of Seattle, his wife permanently disappeared one night by herself; the same night that the father and their two young sons took a sudden, unexplained trip to the desert – which seemed odd to everyone. But while he was a person of interest, he was not formally charged with her murder. In the meantime, he moved in with his father, who turned out to have a fascination with child pornography. His father was arrested for his computer pornography and the court gave temporary physical custody of the two young sons (4-5 years old) to the mother’s parents.

Josh then went to court to fight for custody. The judge said that she could not give him custody until he passed a psychosexual exam, given his father’s pornography interests. In the meantime, he would continue to have supervised visitation with his sons at his home. Four days after the hearing, when his sons came for their visitation with him, he pulled them into the house and shut the door on the supervisor. Minutes later, the house exploded in a huge fire. Forensic evidence later revealed that Josh had killed his sons with blows to the head before setting off the explosion. Could this have been predicted?

Simply using the 90% Rule, it would be easy to know that 90% of people NEVER have a spouse disappear in the night under suspicious circumstances. It was well-known through the news media that Josh was a person of interest in the disappearance of his wife. This doesn’t make him guilty, but it does make him likely to have a high-conflict personality – one which could have a possible pattern of killing people when he felt trapped or otherwise upset.

Using the 90% Rule, the authorities involved in the case and the care of the children could have taken more precautions to protect the children. This wasn’t just an ordinary family court case to be dealt with by having a supervisor at the parent’s home. This was a potential murder case. To be cautious, supervised visitation could have taken place at a more secure setting, such as at the court. Unfortunately, the case was treated as an ordinary custody and visitation case, when in fact it involved serious problems that 90% of people would NEVER have.


The 90% Rule is a short-cut to predicting that there is a possible pattern of high-conflict behavior for a person. If 90% of people would NEVER do the behavior that he or she has engaged in or is seriously suspected of engaging in, this may be a person to keep a careful distance from. Beware of excuses – theirs or your own – which say that this behavior occurred because of stress or being tired or never occurred at all. Of course, this is not a rule by which you could convict someone of a crime. But it could help you avoid hiring someone, dating someone or electing someone who is likely to have a high-conflict personality.

Bill Eddy is a lawyer, therapist, and mediator. He is the co-founder and Training Director of the High Conflict Institute, a training and consultation firm that trains professionals to deal with high conflict people and situations. He is the author of several books and methods for handling high conflict personalities and high conflict disputes with the most difficult people.

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