On Tuesday, the FBI released its annual report on the number of hate crimes committed in the United States. The tally for 2017, 7,175 hate crimes, is the highest figure recorded in a decade, according to one analysis, and represents a 17 percent increase from 2016. The data show hate is intensifying nationwide.

But it’s even more prevalent than FBI numbers suggest.

Some of last year’s most widely reported hate crime charges — the confessed assailant who said “get out of my country” before killing Srinivas Kuchibhotla; the death of Heather Heyer, allegedly by a white supremacist who ran her over in Charlottesville; and the Portland MAX train stabbings, during which the accused attacker was overheard yelling racist slurs — are not recorded in the FBI report.

Under the 1990 Hate Crime Statistics Act, the Department of Justice is required to compile data on “crimes that manifest evidence of prejudice based on race, religion, sexual orientation, or ethnicity.” The job falls to the FBI, which releases an annual report. But the FBI depends on a huge range of law enforcement organizations to tell it when this has happened – and they are completely unreliable.

The problems begin with the way agencies collect the information: As ProPublica reported last year, only 12 states require police to learn how to identify and investigate hate crimes during the academy, and few agencies provide training after officers leave the academy. A longstanding federal training program that used to send experts around the country to teach police how to respond to hate crimes was abandoned during the Obama administration because local authorities wanted to concentrate more on Islamist violent extremism rather than white supremacist violence.

In some cases, trainers with racist agendas have filled this void. For example, individuals affiliated with the Islamophobia industry — junk scientists and think tanks that promote dangerous falsehoods about Muslims — have been training law enforcement on how to engage with Muslim communities for years. These trainers are well funded and connected to organizations like the National Sheriffs’ Association. The result is that police officers don’t have a full understanding of what constitutes a hate crime and are unlikely to accurately track them. Perhaps this is why the murder of Khalid Jabara by his next-door neighbor, a white supremacist known to police, in Tulsa in August 2016, was not reflected in the FBI’s 2017 hate crime report.

Even when police officers document and report hate crimes to local and state authorities, they often don’t make it into the FBI report. A study by the Associated Press, for example, found that about 17 percent of all city and county law enforcement agencies didn’t bother to submit a single hate crime report from 2009 to 2014. ProPublica found that of agencies participating, 88 percent disclosed no hate crimes in 2016. Encouragingly, the number of agencies that contributed data for the 2018 report rose 6 percent.

There is no single explanation for this problem. Authorities are sometimes confused by the patchwork of state and federal hate crime laws and don’t know when to report; others mistakenly believe that an incident has to be prosecuted as a hate crime to count as one; and still others make tabulation errors, sometimes exacerbated by the use of outdated reporting methods, having not yet implemented the National Incident-Based Reporting System.

Sometimes the reasons are more nefarious — agencies don’t report hate crimes, or they lie about them, because officials want to mask the racism and bigotry that exist in their communities. As I traveled the country in the wake of the 2016 election to document hate crimes, survivors, advocates and community organizations repeatedly expressed this sentiment.

Congress, meanwhile, continues to look the other way and fails to provide responsible oversight. Hate crime reporting by local authorities remains voluntary not mandatory, and that will not change, unless Congress acts. There is currently no penalty for failing to report, and so the actual number of hate crimes committed in the United States is many times greater than what the FBI reports. According to the Justice Department’s National Crime Victimization Survey, the annual number is closer to a quarter-million hate crimes each year. That’s the figure that community organizations and affected communities generally use, and the press should follow their example.

Some survivors already choose not to report because they fear surveillance, deportation if they are undocumented or revealing their sexual orientation or gender identity. And since many local police departments clearly don’t treat hate crimes as priorities, the belief is widespread among survivors that authorities can’t be trusted, I found in my reporting. Instead ,many survivors have responded to the spike in hate by creating neighborhood watch programs, building hate free zones and taking self-defense classes. In December 2016, for instance, the Providence Youth Student Movement didn’t call the police after a hate crime targeted their office. They introduced a buddy check-in system and enrolled their staff in self-defense training.

Clearly police departments are capable of collecting and using big data. They routinely rely on criminal histories and location information to generate threat scores and identify hot spots as part of predictive policing programs. Some law enforcement agencies share arrest and detention records of undocumented immigrants with ICE to assist in detention requests. A few agencies have embraced surveillance technologies, such as license plate readers and closed-circuit TV cameras, to monitor and track the daily movements of citizens. When it comes to policing and targeting vulnerable communities, data are elixirs. When it comes to protecting vulnerable communities, data are impediments.

Still, data alone won’t save us. Authorities must meaningfully take on white supremacy. The greatest threat facing this country is homegrown white supremacists, not Muslims or refugees. A joint FBI and Department of Homeland Security 2017 intelligence bulletin warned that white supremacist groups had already carried out more attacks than any other domestic extremist group over the past 16 years and were likely to carry out more attacks over the coming year. Perhaps an attack like the tragedy at the Tree of Life Synagogue could have been averted, if these warnings were heeded.

Many of us know and agree that the Trump administration has emboldened and incited hate across this country. The rhetoric and policies stigmatize and threaten vulnerable communities everyday. And yet the FBI report, and its glaring omissions, show that the problem is much worse than many realize.

Correction: An earlier version of this article referred to the 2018 FBI report as the 2017 report. The date reference has been updated.