What is the Law of Unintended Consequences?

Tricia Christensen
Tricia Christensen

The law of unintended consequences is the outgrowth of many theories, but was probably best defined by sociologist Robert K. Merton in 1936. Merton wrote an article, The Unanticipated Consequences of Purposive Social Action, which covers five different ways that actions, particularly those taken on a large scale as by governments, may have unexpected consequences. These “reactions,” may be positive, negative or merely neutral, but they veer off from the intent of the initial action. Merton also described five reasons why a “law” or change might fall under the heading of the law of unintended consequences.

An example that illustrates the law of unintended consequences is a family wanting to spend time together watching TV coming across a scene that frightens or upsets the child, thus disrupting the intent of the evening.
An example that illustrates the law of unintended consequences is a family wanting to spend time together watching TV coming across a scene that frightens or upsets the child, thus disrupting the intent of the evening.

The two top reasons why the law of unintended consequences works, according to Merton, is that the framers of a social change are either ignorant of possible far reaching effects of the law or make errors when they develop a change that don’t have the effects they desired. Other reasons why we sometimes see changes occur after any type of event, new scientific development, or treaty is passed may have to do with “self interest,” so much so that a person who desperately wants to see a change doesn’t evaluate the ultimate effects of that change.

A person’s value system may also fail to make them look past their system when taking an action of any kind to evaluate how the law of unintended consequences might work. The fifth cause of the law of unintended consequences is the self-defeating prophecy. In this case, Merton was specifically referring to how society might falsely predict some potential threat to society and to avoid it, might change the society in some important or drastic way.

Any action, from smallest to largest, can have unforeseen results. In a way this is to be expected because even in the smallest systems, like an individual family, individuals are intensely complex beings. When you look at a society as a whole, the mechanisms of it are so convoluted and extraordinarily challenging, that you can expect almost anything that would affect that society to have unintended results.

You could look at how the law of unintended consequences occurs in a family system. For instance, you might decide to sit down with the kids to watch a family movie. The intent may be partly self-interested, since you want to see the movie, and if you’ve never seen it before you may be ignorant of the possibility of consequences occurring from watching the film. Say the five-year old in the family gets badly scared by something that you would view as innocent.

Though the goal may have been to watch the film and have some family time, an unforeseen result rears its head, and you then have a kid who interrupts your sleep for the next year by having nightmares. Sometimes you can’t guess at what an unintended consequence might be. A child might alternately be so impressed by the movie that he or she grows up to be an actor, screenwriter, or a director. These aren’t the goals of family movie night; they’re unanticipated consequences. But the example suggests that even the smallest action can have either negative repercussions or life-altering affects you probably would not have considered.

More frequently, people evaluate how the law of unintended consequences operates on a much larger scale. For example, welfare programs, designed to aid families in economic distress led to the unintended consequence of some folks deliberately staying on welfare and “abusing the system.” This led to welfare reform, especially as enacted by the Clinton era of the 1990s, when people were given a limited time to pull their lives back together.

An unintended consequence of welfare reform was the bind it placed many single mothers in. Since they had to return to work, and they still might lack training to take on high paying work, they had to struggle to find childcare that would be inexpensive enough. Some women who participated in the US welfare to work program found themselves in even greater poverty once they began to work, and the need for inexpensive childcare placed an undue burden on the childcare system, and occasionally placed children in childcare programs that were not well run.

Just about every law, every invention, every treaty, and every large-scale action has unintended consequences, which may alter society as a whole. The advent of antibiotics ushered in cures for illnesses that had previously proved death sentences, but an unintended consequence was the development of superbugs that resist antibiotic treatment. It may be impossible to fully anticipate how any change to a society may ultimately affect it, in many ways, until those effects are already occurring. It’s a law often observed best in hindsight.

Tricia Christensen
Tricia Christensen

Tricia has a Literature degree from Sonoma State University and has been a frequent wiseGEEK contributor for many years. She is especially passionate about reading and writing, although her other interests include medicine, art, film, history, politics, ethics, and religion. Tricia lives in Northern California and is currently working on her first novel.

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Discussion Comments


@Sunny27 - I agree with you. Some kids lack maturity and that sometimes comes from sheltering a child too much. I think that unintended consequences can also come from legal cases that are mishandled.

There have been many cases in which the evidence was tainted or the confession was unlawfully obtained and that resulted in a dangerous criminal going free.

This reminds me of when Governor Huckabee from Arkansas released a violent criminal that turned around and killed another women. This is definitely an untended consequence because the Governor did not think that this would happen.


@Bhutan - I know what you mean. I also think that sometimes our actions lead us to the opposite results that we want.

For example, a parent that is overprotective does not allow a child to learn from their mistakesd by not allowing them to make any mistakes during their childhood; the child grows up ill prepared for adulthood and makes all kinds of disastrous mistakes.

Sometimes the mistakes are based on rebellion, but it is still heartbreaking when this happens. I had a cousin whose parents were so strict that when she went away to college she ended up flunking out because she could not stop partying.

Everything that she was not allowed to do as a teenager she made up for in college and she lost her scholarship and had to start over.

Clearly her parents saw these unintended consequences as a huge problem that may have been prevented if she had a little more freedom when she was younger.


@Bhutan - I could not agree more. I also think that many companies will pay the fine for not covering their employees instead of paying the extra fees for the new health care plan.

This is one example of the unintended consequences, but another involves when the government raises taxes. In the 1970’s, the top tax rate was 70%, and unemployment was over 10% because companies had to lay off employees in order to accommodate for the added tax expense.

This is a law of unintended consequences in economics because instead of the country getting more tax revenue because of the higher tax rate, they received less because less people had jobs that were paying into this tax revenue fund.

In addition, the wealthy, opened offshore accounts and used other tax loopholes in order to secure their wealth instead of spending it on the economy.


I have to say that the law of unintended consequences can be seen in the health care reform bill. This bill intended to offer more health coverage for more Americans and it sounds like a noble claim until you realize the negative consequences associated with the bill.

For example, since there is a mandatory coverage for people with preexisting conditions everyone’s insurance premium will increase my about $3,000 a year.

In addition, the fact those doctors will have to cut their reimbursements by 25% will also cause a lot of doctors to leave the profession. I recently read that something like 40% of doctors would leave the field, which causes the doctor shortage to reach really scary levels.

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