Experience hateful bigotry, say something. That should be the watchword for victims of antisemitism.But across Europe, the United States and Australia, where governments dutifully track such incidents, authorities agree that official numbers understate the problem because victims are hesitant to report them.That reluctance was a main finding of the European Union Fundamental Rights Agency (FRA) survey of Jewish communities in nine EU member states in 2012. One revealing conclusion then, as quoted in a new FRA report, was that “few EU Member States record anti-Semitic incidents in a way which allows them to collect adequate official data.”Indeed, for the new report, covering 2016, half of the 28 EU member states did not provide any data. In addition to the hesitance of victims to contact authorities, the lack of uniformity in reporting hate crimes across the region and within individual countries “contributes to the gross under-reporting of the extent, nature and characteristics of the anti-Semitic incidents that occur in the EU.”But the difficulty of adequately tracking antisemitism is not unique to Europe.The latest FBI hate crimes report found that 54% of crimes motivated by religious bias in the US in 2016 targeted Jews.A Washington Post editorial observed that “The FBI’s statistics on hate crimes, while the best we have, are also incomplete – partly because it’s up to state and local police departments to decide whether to provide the federal government with their data.” The Post also pointed out that a US Bureau of Justice Statistics study “suggests that many hate-crime victims never report the offense.”The BJS “found that only 35 percent of hate crimes are ultimately reported to the police,” and police departments “may not track hate crimes, or victims may not report hate crimes to the police,” reported VOX News, which concluded that while the annual FBI report “is the closest thing to a nationwide database,” there actually is “no system that accurately tracks hate crimes in the U.S.”And when the Executive Council of Australian Jewry reported last month a 10% rise in the number of reported antisemitic acts, Tim Soutphommasane, Australia’s race discrimination commissioner, said, “The difficulty with monitoring racism is that the vast majority of incidents go unreported.”One effective way to mobilize government action is convincing them to adopt the Working Definition on Anti-Semitism.“To be successful in combating antisemitism we must first understand it,” says Rabbi Andrew Baker, AJC’s director of International Jewish Affairs, who also serves as the personal representative on combating antisemitism for the Organization for Security and Cooperation in Europe (OSCE). The Working Definition “is a necessary educational tool, which increases public awareness and helps government authorities more effectively address the security concerns of Jewish communities.”To date the 12-year-old definition has been adopted by Austria, Bulgaria, Germany, Romania, the United Kingdom, the International Holocaust Remembrance Alliance (IHRA), which includes 31 countries, and the European Parliament.But the definition alone does not necessarily lead to better data collection.Not surprisingly, countries with relatively large Jewish communities, such as France and Great Britain, capably monitor and report antisemitism.France’s Service for the Protection of the Jewish Community (SPCJ) and Interior Ministry are working together to obtain more accurate data. The new FRA report confirms that the SPCJ “replicates the data” from the CNCDH (French National Consultative Commission on Human Rights).In the UK, the Community Security Trust (CST) signed an agreement in 2015 with the National Police Chiefs’ Council to better track and coordinate collection of data on antisemitic incidents.In 2014, France became the first EU member state to create a senior government position, reporting directly to the prime minister, with the responsibility of leading the battle against antisemitism. Following a government plan launched in 2015 to take the fight to all sectors of French society, recorded antisemitic incidents dropped from 851 in 2014 to 335 in 2016, and that downward trend has continued during 2017.In October 2016, Bulgaria’s deputy foreign minister was appointed the country’s national coordinator on combating antisemitism.And AJC Berlin, among others, has renewed its call for the German government to appoint a Federal Commissioner for Anti-Semitism Affairs to coordinate government responses to antisemitism, and to step up prevention measures.Persistent violence targeting Jews and Jewish institutions challenges governments, civil society and Jewish communities to maintain constant vigilance, devise new ways to organize more effectively to monitor offenses, respond when they occur, and – importantly – prevent future incidents.As antisemitism has evolved and expanded from vandalism of synagogues and cemeteries to violence against Jewish individuals and institutions, and to the Internet and social media, where anonymity enables the perpetrators to operate without fear, it is imperative to figure out how to collect the most accurate and detailed data.Knowledge about the nature of the incidents and who is behind them will help government, civil society, law enforcement, educators and others develop and implement strategies and programs to counter and defeat the purveyors of antisemitism.A new, expanded FRA survey is planned for 2018 that will cover 13 countries, four more than the 2012 study. They will include Austria, Belgium, Denmark, France Germany, Hungary, Italy, Latvia, Holland, Poland, Spain, Sweden and the UK.To prepare for the likely conclusion that tracking antisemitism remains a seemingly insurmountable challenge, we should discuss now how to establish better, more standardized methods, and create a reliable database.The writer is the American Jewish Committee’s director of media relations.