criminal background checks

This is the first of three posts about the INFORMS Annual Meeting.  Check back in the next few days for the other two posts.

I thoroughly enjoyed the Threats to Life and Limb session.  Thanks to Arnie Barnett for organizing a great session!

In this session, Al Blumstein gave a provocative talk about criminal recidivism.  His research is motivated by employe background checks.  Since most records are electronic, arrest records from the distant past survive.  In many cases, a reformed individual could be denied employment for a minor indiscretion committed decades previously.  The data indicates that more than 50% of the population will have a non-traffic related arrest at some time in their lifetime, making this a huge problem.  However, most of these arrests are for youthful indiscretions.

Blumstein proposes developing hazard curves (based on age of first arrest and type of crime committed).  The hazard rates quantifies the likelihood of someone being arrested for the first time after a given amount of time has passed.  Blumstein uses these hazard rates to determine when a distant, initial arrest should be ignored after someone has been clean long enough.  Blumstein’s research assumes that being “clean” means not being arrested, since background checks only see if arrests have occurred (not whether someone is committing crimes that are undetected).

Blumstein’s results are provocative and generated quite a stir within the session.   Based on the age of first arrest and the type of crime, it takes about 4-8 years of a “clean” record to have a hazard rate similar to the general population.   Since many employers ignore criminal records older than seven years, and they would be on track.

The general population, however, contains many criminals that we probably don’t want to hire.  A better solution may be to compare those with a criminal record to a law-abiding population instead (those who have never been arrested).  The probability of being arrested in a given year is about 10% for the general population and about 1% for those who have never had a prior arrest.  Of course, a former criminal has to stay clean much longer to be “good as new.”  In fact, the hazard functions of the former criminals and the never arrested never overlap.  You can compare the two hazard rates when they get “close enough.”  The confidence intervals here are pretty wide, but Blumstein’s results suggest 10-20 years of being clean.

Blumstein’s research will hopefully be used to create guidelines for employer background checks (in terms of when they can ignore distant arrests).  Criminal justice needs good OR.

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6 responses to “criminal background checks

  • iamreddave

    “The general population, however, contains many criminals that we probably don’t want to hire” Say it makes sense for an individual company not to hire a former criminal. What is the societal damage from all these former criminals never getting jobs? If a criminal conviction is “I sentence you to 2 years in prison and 20 years being unemployed” does it 1. Reduce first crimes 2. Increase crime amongst those already convicted?

  • Laura

    Good question, iamreddave.

    Most of the “former criminals” are people with minor drug-related arrests (like marijuana possession), who receive no jail time. I have to admit that it seems silly (and wrong) to deny them employment for decades to come. I am slightly less enthusiastic about fighting to restore employment rights to those convicted of more serious crimes. It depends on the type of job and the type of crime, I suppose.

    An anecdotal example given during the talk is that background checks are performed for people assisting seniors in a certain housing development for the elderly. No one with drug-related arrests were allowed there. A ~50 year old man with a drug-related arrest (possession) committed when he was a teenager was not allowed to assist his sick, elderly mother whereas someone who had been convicted of murder would have been allowed. According to Blumstein, such anecdotal stories are extremely common. Identifying these injustices is easy but replacing them with something based on analytical reasoning is more challenging. Using OR to fight for justice is pretty punk rock.

  • Nick


    Perhaps it’s not in the company’s best interests to take the risk of hiring a criminal, as you indicate, regardless of how society might benefit. By not hiring a ‘risky’ individual they avoid any higher-than-normal costs off their payroll and into society at large where there’s a larger pool of money to deal with costs incurred because the individual they didn’t hire is breaking the law again. I make no judgment call, but note that it’s rational for a company to make a decision like that.

    The court sentencing decision does not, at this time that I’m aware of, include any third-party impacts of sentence (i.e. how would 5 vs 8 years in prison impact their ability to get a job later) since the court system has no control over that. If it’s a problem regardless of how long the sentence is (1 vs 5 vs 8 years), then the issue isn’t that they’re sentenced (1 year prison and 20 years unemployed vs 5 in prison and 20 unemployed) but that they committed a crime in the first place, were caught, and convicted.

  • Mike K

    I wonder if the presence of a criminal/arrest record, or at least its availability to a potential employer, helps to skew the statistics: If someone cannot find a job because of their record, is that going to make them more likely to offend than they would if their record were hidden and they could hide their record (within certain limits)? What happens when you adjust re-offending rates for employment status and even income (or have you already?)

    The UK, for example, has a notion of ‘spent’ convictions which are automatically removed from your (public) police record after a certain period: Five years for convictions with no custodial sentence, seven years, if the sentence was six months or less, and ten years if the sentence was from 6 to 2.5 years inclusive – and that broadly coincides with Blumstein’s answers.

    The other thing, of course, is that as soon as you are arrested, the police will know you and might have you marked out as a criminal, and when something similar happens again in your neighbourhood, the police will be knocking at your door first, whether or not you’ve you were involved. So your subsequent chances of arrest could be determined in part by police practices as well as your own criminal tendencies.

    Look at the manner in which the criminal checks are being conducted and how the company in question reacts to the results, particularly how much discretion the hiring manager has: If a small informal company were doing a background check and discovered a 1969 conviction for half an ounce of cannabis possession, would the hiring manager have greater discretion, and would the applicant have a better chance than at a larger firm which may have a written drugs policy.

    Final question is what is the extra absolute risk of an ex-arrestee re-offending, what is the damage he can do. If the chances of a clean person offending against the company are 1 in 1,000,000 and the average offence is stealing a box of paperclips, then even a tenfold increase risk isn’t going to cost the company very much.

  • Laura

    Excellent points, Mike K!

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