Here are eight factors that could be cited as causes of wrongful convictions in the United States. Much of this is based on the source in the link below.
- Mistaken eyewitness testimony. This is by far the most important cause of wrongful convictions. The problem here is that juries tend to put great stock in eyewitness testimony. They feel that a person who was actually at the scene of the crime will provide the best kind of evidence. This causes wrongful convictions because human memory is not infallible the way people think it is. The best way to reduce wrongful convictions would be to educate jurors about the limitations of eyewitness testimony.
- False confessions. This factor seems odd to people because it seems unlikely that anyone would ever confess to a crime that they had not committed. However, research does show that many people, under psychological pressure, will actually confess to crimes that they did not do.
- Government misconduct. Prosecutors and police are often motivated to get as many convictions as possible. They also can be susceptible to believing someone is guilty and then doing whatever they can to convict the person. These tendencies lead them to, at times, engage in misconduct in order to get convictions. This sometimes leads to innocent people being convicted.
- Bad science. Prosecutors often use “scientific” methods of analyzing evidence that are not really trustworthy. The methods sound good, convincing juries of their accuracy, but they are not as legitimate as laypeople think.
- Use of informants. This, in my view, is a subset of government misconduct. Prosecutors and police often use informants to give evidence against people accused of crimes. This sounds logical because informants can run in the same circles as the accused and can hear things the police don’t get to hear. However, informants often have strong motives for giving false evidence. They can, for example, give false evidence to get money or to get out from under legal trouble themselves.
- Inadequate defense. People in the US who cannot afford a lawyer are given court-appointed lawyers. These lawyers are almost always overworked and are often not the best lawyers around. This can lead to sloppy work on their part. Innocent people can be convicted because their lawyers were not smart enough or attentive enough to see holes in the prosecution’s evidence or because the lawyers were too overworked to give enough time to their cases.
- Pro-police bias. Juries tend to be made up of law-abiding people who trust the police and government authority. They tend to believe what the police and the prosecution say much more than they tend to believe defense attorneys and witnesses. This can lead them to give more credence to the prosecution’s case than it deserves, thus causing wrongful convictions.
- Racism or other bias against defendants. Criminal defendants are disproportionately poor and non-white. They often come from a totally different socio-economic stratum than juries do. Juries can be, whether consciously or not, biased against these defendants who are not “like them.” This, when combined with the previous type of bias, can lead to wrongful convictions.