In its amicus brief, the Department of Justice relies in part on flawed research findings as evidence that AR-15s are in “common use” and cannot be prohibited. For example, the Department cited a survey released days before briefs were due by a professor, William English, whose earlier work was criticized for — among other things — having “undisclosed ties to pro-gun interests.” English’s new research claims that roughly a quarter of gun owners own AR-15s. However, the new survey appears to suffer from many of the same flaws as his prior one; it was not peer-reviewed, does not disclose how respondents were recruited, and primes respondents to answer in certain ways.