How Many Guns Are Sold Without Background Checks

Universal background checks are favored by more than xc% of all Americans (ane). Legislation requiring groundwork checks for private firearm sales has been strongly endorsed by leading U.S. medical (2), legal (2), and law enforcement organizations (3). Despite this support, most states practice not require background checks for firearm sales betwixt private parties. The extent to which the absenteeism of requirements for universal background checks contributes to the more than 33 000 annual firearm deaths in the United states (4) is unknown, in part because even the most basic information about groundwork checks is not routinely nerveless. For example, no routinely collected data bespeak how ofttimes firearms are transferred from i individual party to another, where and between whom these transfers occur, or how often they involve background checks. What is known is that many gun offenders obtain the guns they employ in law-breaking through private sales. For example, a survey of prisoners bedevilled of gun offenses revealed that 96% of inmates who were prohibited from possessing a firearm at the time they committed their crime had obtained their firearm from an unlicensed private seller (v). Other studies identify unlicensed private sellers every bit major contributors to illegal firearm trafficking within the United States and across the U.South.-Mexico border (6, 7).

Because routinely collected data exercise not provide estimates of where firearms exchange hands later entering the U.S. market, or the extent to which secondary transfers are subject to background checks, researchers have relied on national surveys, the most recent of which was a random-digit dialing survey conducted in 1994, to approximate the proportion of U.Due south. gun owners who obtain firearms without a background cheque (eight). That survey asked gun-owning respondents whether they had acquired firearms during the previous 2 years and, if so, whether their nigh recent conquering had been "from a federally licensed firearms dealer" (the proxy used for having undergone a background bank check). As reported first past Melt and Ludwig (eight), approximately 40% of gun-owning respondents who had acquired firearms between 1992 and 1994 did so without a background check. No contemporary estimates exist.

We believe the current report is the first in more than than xx years to update and extend information well-nigh where, when, and how electric current U.Southward. gun owners acquired their most recent firearm and whether the transfer involved a background check. We enumerate the proportion of current gun owners who acquired their about recent firearm without undergoing a groundwork cheque past acquisition type (purchased vs. nonpurchased), subtype (where acquired, from whom), and recency of conquering. In addition, although federal law does not crave background checks for firearms transferred between individuals who are not licensed dealers, some states exercise (9); therefore, we examine, by state-constabulary status, the proportion of gun owners who underwent a background check for those acquiring their terminal firearm through a private auction.

Methods

Pattern and Sampling

Information come from a nationally representative, Spider web-based survey designed by the investigators and conducted in April 2015 past the survey firm Growth for Knowledge (GfK). Respondents were fatigued from GfK's KnowledgePanel (KP), a grouping of approximately 55 000 U.S. adults selected (on an ongoing basis) with an equal probability of pick. The study-specific recruitment rate (proportion of individuals who were eligible for our study and agreed to become panel members) was 14.4%. All panel members, except those currently serving in the U.Southward. Armed Forces, were eligible to participate. Gun owners and veterans were oversampled from the KP; sampling weights supplied by GfK were applied such that estimates from the survey are representative of U.Due south. adults (anile ≥ xviii years) in 2015. Invitations to participate were e-mailed; one reminder electronic mail was sent to nonresponders 3 days later. Participants did not receive any specific incentive to consummate this survey, although GfK has a point-based program through which participants accrue points for completing surveys and tin can redeem them later for greenbacks, merchandise, or participation in sweepstakes. Additional details of GfK's survey blueprint are described in the Appendix.

The Northeastern University Institutional Review Board approved the report.

Measures

The full survey, conducted in Apr 2015, was designed to examine patterns of civilian gun ownership, storage, and use. Information technology adamant gun ownership status and whether the possessor's most recently caused firearm was obtained with a background cheque but did not inquire about the timing of the almost recent acquisition. To determine when, relative to the original survey, respondents acquired their most recent firearm, GfK invited all gun-owning respondents from the April 2015 survey to answer additional questions in Nov 2015 (Figure).

**Figure. Recruitment and participation of panel members.**
KP = KnowledgePanel.

Gun ownership condition was determined on the basis of responses to 2 questions, the beginning beingness, "Exercise you or does anyone else you alive with currently ain any type of gun?" Those who answered affirmatively then were asked, "Practise you personally own a gun?" Respondents too were asked almost their most recent firearm acquisition, including the type of gun (for example, handgun or long gun), whether they bought the gun or acquired information technology in some other way (such as through an inheritance), and where they acquired the firearm (for case, a gun store). Information regarding groundwork checks are but from respondents who personally endemic guns.

To determine what proportion of current firearm owners underwent a groundwork check for their most recently caused firearm, nosotros asked all gun owners, "Equally far equally you know, as part of the transfer, did you undergo a background check?" All gun owners also were asked, "Did the person who sold you a gun ask you to show a firearm license or permit before buying the gun?" Respondents could answer "yes," "no," or "no opinion/don't know" to both questions. If the response to either question was affirmative, we classified that transfer as having involved a background check. Respondents who answered "no stance/don't know" to the background bank check question were included in primary analyses later imputation (described after).

In the supplemental November 2015 survey, all gun owners from the original survey however in the KP were invited to answer 2 additional questions about the timing of their nearly recent gun acquisition. The first question was, "When you lot completed the prior national firearms survey, sponsored by Northeastern University, in Apr 2015, you lot said that the gun yous acquired about recently was a [insert type based on type noted in the April 2015 survey]. Thinking about this gun, approximately when did you acquire information technology?" Three options were offered: "within the past 2 years," "between 2 and five years ago," and "more 5 years ago." The second question was, "What was the exact yr that you acquired this gun?" Respondents were asked to specify the exact yr or to written report that they did non know the year.

Land Firearm Legislation

Land laws regulating individual firearm sales by and large crave that before a purchased firearm can be transferred between private parties, the prospective purchaser undergo (and pass) a criminal history background cheque. For the state-level analyses, if a land had implemented a private sales law by 1 July 2013, it was coded as having such a law for the analyses involving firearms acquired within the by ii years. Washington and Oregon both enacted laws in the latter function of 2014 and therefore were coded every bit not having a background check law (x). For the analyses involving firearms acquired more than than 2 years before the survey administration, Colorado and Delaware were coded as not having state laws considering they implemented laws subsequently 1 July 2013 (10). We assumed that the state in which each respondent was living at the time of the survey was the country in which he or she had acquired his or her almost contempo firearm. Firearm purchases made between individuals, at a gun show, or online were coded equally individual sales, but those that occurred at stores or pawnshops, which past federal constabulary are required to exist licensed every bit firearm dealers, were non.

States with laws regulating private sales as of 1 July 2013 include California, Colorado, Connecticut, Delaware, Hawaii, Illinois, Iowa, Maryland, Massachusetts, Michigan, Nebraska, New York, N Carolina, Pennsylvania, Rhode Island, and Washington, DC. Except for Colorado, which enacted its law in 2013, and Delaware, which in 2013 converted its constabulary from optional to mandatory, other states that regulate private sales enacted their laws before 1996 (Table ane). All states with private-sales legislation regulate handgun sales; 11 regulate long-gun sales (long guns include rifles and shotguns) (ten).

Table ane. State Laws for Secondary Sales*

Weighting and Analysis

To ensure reliable estimates at the national level, our survey oversampled gun owners by using GfK demographic profile variables, and so used the gun-owning questions in the April 2015 survey to verify gun buying. The GfK group provided final survey weights that combined presample and written report-specific poststratification weights to account for oversampling and for nonresponse to both the April 2015 and November 2015 surveys. Additional details near survey weighting are bachelor in the Appendix.

Regarding the groundwork bank check question, 148 respondents (23 of whom acquired their nearly recent firearm inside 2 years of the survey) answered "no opinion/don't know." Nosotros did non believe these responses represented an informative event; therefore, in primary analyses, nosotros used multiple imputation to account for these "missing" responses for our issue of interest. Multiple imputation for missing values was washed by using logistic regression under the missing-at-random assumption. The imputation model included predictors of background check status: place and type of firearm transfer; timing of transfer; residence in a state with laws regulating individual sales; and additional covariates of age, sex, educational attainment, ethnicity, marital condition, urban or rural residence, and veteran status. We generated 100 multiply imputed data sets, and estimates were derived in Stata, version xiv (StataCorp), by using the "mi" and "svy" suite of commands. An boosted 15 respondents did non know when they caused their firearm and were excluded from analyses that involved acquisition timing simply included in the overall conquering numbers. All analyses used weighting commands (using the weight variable provided by GfK) to generate national estimates reported as weighted percentages, with 95% CIs, following the STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) guidelines for reporting (11).

Nosotros conducted sensitivity analyses to examine how our guess of the proportion of gun owners who caused their virtually recent firearm without a background check varied depending on how we handled respondents who answered "no stance/don't know" to the background check question. First, nosotros categorized all such respondents (north = 148) equally having undergone a background bank check (effectively producing a lower jump for our estimates of what percentage of gun owners did non have a background check). Next, we categorized all 148 respondents every bit not having undergone a groundwork check (producing an upper bound). We conducted 2 additional sensitivity analyses pertaining to respondents who caused their about recent firearm in 2013, because asking respondents to indicate whether they had acquired their most recent firearm "inside the past two years" versus "betwixt 2 and v years agone" may take introduced ambiguity for those who acquired their most recent firearm in 2013. The commencement excluded the 134 respondents who acquired their most recent firearm in 2013 from the "within the past ii years" grouping; the second included all 134 in the "within the by 2 years" grouping.

Role of the Funding Source

The funders did not play a part in the design, conduct, or reporting of the research or in the decision to submit the manuscript for publication.

Results

Of the 7318 invited console members, 4165 started and 3949 completed the April 2015 survey (excluding 48 active-duty military personnel who started the survey but were ineligible to consummate information technology), yielding a survey completion rate of 54.six% (12). Of the 2072 gun-owning respondents in the original Apr 2015 survey, 1880 were even so in the KP in Nov; all were invited to respond the boosted set of questions about the timing of their nearly recent gun acquisition. Of the 1880, 1613 (86%) responded. Respondents to the supplemental survey did non differ from the participants in the original survey with respect to age, sex, race, type of gun most recently acquired, acquisition patterns, or proportion who reported having a background cheque.

Half of our respondents acquired their virtually recent gun within the past five years (29% inside the past 2 years, 21% between two and 5 years ago, and the remainder more than 5 years ago) (Table 2). For gun owners who reported acquiring their terminal firearm inside 2 years of the April survey, 22% (95% CI, 16% to 27%) obtained their almost contempo gun without a groundwork cheque (Table 3). Sensitivity analyses excluding the 134 respondents who caused their most recent firearm in 2013, 79 of whom indicated they had acquired their nearly recent firearm within ii years of the survey, yielded like results: 20% (CI, 14% to 26%). Analyses including all 134 respondents who indicated that they had obtained their concluding firearm in 2013 or thereafter likewise yielded similar results: 23% (CI, 18% to 29%).

Table two. Characteristics of U.Due south. Adults Who Own Guns

Table 3. Summary of Almost Recent Firearm Transfer, by Type of Acquisition*

Amongst gun owners who acquired their nigh recent firearm inside the past 2 years by style of purchase, thirteen% (CI, viii% to 18%) did so without a background check. For gun owners who purchased their most recent gun from a friend or an acquaintance inside the past two years, 77% (CI, 62% to 92%) did so without a background check. For those purchasing online, 45% (CI, 9% to 82%) did non have a background check. Among gun owners overall, regardless of when their most contempo acquisition occurred, seventy% purchased their most recent firearm, and 27% of the latter group (CI, 23% to 30%) did so without a background check. Overall, beyond all periods, 42% (CI, 38% to 45%) acquired their nearly recent firearm without a background bank check.

When respondents who answered "no opinion/don't know" were assumed either to have or to accept not undergone a background bank check, resulting point estimates fell within the 95% CIs of our chief analyses. For example, with respect to firearm transfers within two years of the survey, the lower and upper premises for betoken estimates produced by coding missing data in this manner were 18% and 26%, respectively.

For firearms purchased privately within the past 2 years, 50% (CI, 35% to 65%) were obtained without a groundwork check. Among gun owners who reported obtaining their most recent firearm within the past 2 years past style of purchase from a private seller, those who lived in states regulating private firearm sales reported doing so without a background cheque 26% (CI, 5% to 47%) of the time. Among respondents residing in states without regulations on private firearm sales, 57% (CI, 40% to 75%) of such transfers occurred without background checks (Table 4).

Table 4. Percentage of Current Firearm Owners Whose Almost Recent Private-Sale Firearm Acquisition Occurred Without a BC or the Equivalent, past Land Law Status and Fourth dimension of Transfer*

Give-and-take

The number of new guns available for buy by the U.South. noncombatant population, all of which are subject area to background checks when first acquired, is published annually past the Bureau of Booze, Tobacco, Firearms and Explosives (ATF). The ATF data signal that more 360 one thousand thousand firearms entered the U.S. market between 1899 and 2013, with 16 million entering in 2013 lone (thirteen). These information, however, do non explicate how many of the 55 million U.S. adults who currently own firearms (9) obtained their guns without background checks.

Our finding that 22% (CI, xvi% to 27%) of gun owners who recently caused firearms did so without a background check is lower than the 1994 estimate of "about" 40% (8), which was based on a survey with 2568 respondents (789 gun owners, 251 of whom acquired a firearm within 2 years of the survey) and a 1.4% margin of mistake for the full sample. No CIs around the 40% statistic were reported. The apparent decline in firearm conquering without background checks over the past 2 decades, based on comparison our findings with those from the 1994 survey, cannot be attributed to differences in the period assessed (both surveys focused on the 2 years before the survey). Our survey asked respondents explicitly near groundwork checks and permits or licenses to buy, and the 1994 survey asked respondents whether their last acquisition was through a federally licensed firearms dealer. However, the differences in how the 2 surveys assessed groundwork check status also seem unlikely to explain the apparent decline in the proportion of gun owners who reported non having undergone a groundwork check for recent acquisitions. In the 1994 survey, for case, some respondents were not certain whether the source was a federally licensed firearms dealer, and others indicated that the source was a federally licensed firearms dealer merely then reported that the transaction was a trade rather than a cash auction or that the source was an acquaintance or a family unit member (viii). Regardless of which of these cases were included or excluded, the proportion without a groundwork check ranged from 36% to 43%. Also, sensitivity analyses in our survey produced similar estimates regardless of whether nosotros imputed groundwork check condition for respondents who indicted "no opinion/don't know" to the background check question, as in our primary analyses, or eliminated these respondents from analyses altogether. Fifty-fifty when we generated upper and lower bounds for our betoken estimates by assigning all such respondents to either having had or non having had a groundwork check, estimates of the proportion of gun owners who did not have a background check ranged but from 18% to 26%. Lastly, results within our 2015 survey are consistent with a pass up since 1994: 31% (CI, 25% to 34%) of current gun owners who obtained their last firearm between 2 and 5 years earlier our survey and 57% (CI, 53% to 62%) whose last conquering was more than 5 years before our survey reported completing the transaction without a groundwork bank check.

One reason background checks have become more than common in recent years is that compared with gun owners who acquired their near recent firearm several years ago, those who acquired a gun more recently are more likely to have purchased their firearm from a store (where background checks are required by federal police force), as Table 2 indicates. Another factor may be that several states have enacted background check regulations for the individual auction of firearms. Consistent with the goals of these state-level regulations, we found that 26% (CI, five% to 47%) of gun owners who lived in a country regulating individual sales and who purchased firearms from a private seller in the past ii years did and then without a background check, compared with 57% (CI, 40% to 75%) of those who lived in states that adhered to federal requirements alone.

Every bit with findings from all self-reported surveys, our report's results should exist interpreted in light of potential inaccuracies due to recall and social desirability bias (14), especially for respondent answers that relate to more remote periods. In addition, firearm owners may have acquired their gun in a country with private-sale laws that differ from those of the state in which they resided at the time of the survey. For these reasons, we emphasize our findings related to firearm acquisitions within 2 years of our survey. With respect to potential inaccuracies due to recall and social desirability bias, research suggests that online panel surveys, such equally ours, may reduce social desirability bias and yield more than accurate estimates of respondent characteristics compared with phone surveys (fifteen, xvi). Another advantage of online panels is high completion rates for those who brainstorm the survey and the availability of information almost panelists who practice non elect to take the survey in the commencement identify (12). In our written report, 99% of respondents completed the survey, fewer than i% declined to answer our stem question about household gun ownership, no one declined to answer the subsequent question regarding whether they personally owned a gun, and fewer than two% declined to answer the background check questions. Finally, our survey completion charge per unit (55%) is college than the rates for typical nonprobability, opt-in, online surveys, which are 2% to sixteen% (12); higher than those of previous national injury surveys that included questions about firearm ownership (17, 18); and similar to those from other surveys conducted past GfK (19). Nevertheless, panel members who chose not to participate in our survey may have differed in important ways related to the likelihood of undergoing groundwork checks compared with panel members who chose to participate.

In 2015, 8 national health professional organizations and the American Bar Clan called for legislation requiring groundwork checks for all firearm sales between private parties (2). In providing empirical context, the alliance estimated that half-dozen.6 1000000 firearms are sold annually without background checks, an extrapolation based on the about recent data bachelor: the 1994 National Survey on Private Ownership and Use of Firearms, which found that approximately 40% of gun owners who had recently acquired a firearm did so without a background cheque (eight). Although our estimate suggests that a smaller proportion of gun owners (22%) obtain firearms without background checks today than in the by, our findings still indicate that millions of U.Due south. adults annually continue to larn guns without background checks, often from friends or acquaintances, and unduly so in states that do non regulate private firearm sales.

Appendix: Detailed Survey Methods

Study Pattern

Northeastern University (master investigator, 1000. Miller) contracted GfK (formerly Knowledge Networks; world wide web.gfk.com) to behave the National Firearms Survey, which aimed to examine firearm ownership and use in the United States. The survey was washed in a sample from KP, an online research panel that represents the unabridged U.S. population.

KP Details

Panel members are recruited by GfK randomly through probability-based sampling, and households are provided with access to the Internet and hardware if needed. For recruiting, GfK uses address-based sampling methods (previously it relied on random-digit dialing methods). After accepting the invitation to join the panel, participants are asked to complete a short demographic survey (the initial profile survey), answers to which let efficient panel sampling and weighting for future surveys. Completion of the contour survey allows participants to become panel members, and as in the by, all respondents are given the same privacy terms and confidentiality protections. For our survey, the contour rate was 63.8%, defined as ((Profile Completes))/((Profile Consummate+Partial Profile Consummate)+(Contour Refusals+Profile Noncontacts+Other Profile Cases)).

One time household members are recruited for the panel and assigned to a study sample, they are notified by e-post for survey taking, or panelists may visit their online member page to accept the survey (instead of being contacted by telephone or postal mail). The latter approach reduces the burden placed on respondents considering e-mail notification is less intrusive than phone calls, and nigh respondents detect answering Spider web questionnaires more interesting and engaging than being questioned by a telephone interviewer. Furthermore, respondents accept the convenience of choosing what time of day to complete their assigned survey. To assist console members with their survey taking, each member has a personalized "home folio" listing all the surveys that have been assigned to him or her and take yet to be completed.

Additional documentation regarding KP sampling, data collection procedures, weighting, and issues related to institutional review lath approval is available at the following online resources:

www.knowledgenetworks.com/ganp/reviewer-info.html

www.knowledgenetworks.com/knpanel/docs/knowledgepanel(R)-pattern-summary-description.pdf

www.knowledgenetworks.com/ganp/irbsupport/

Sampling

The parent survey used for this report was conducted in a target population comprising adults aged xviii years or older who fell into one of 3 groups: gun owners, non-gun owners living in a gun-owning household, or not-gun owners living in a non-gun-owning household. An additional target population was veterans (who could fall into any of the 3 same groups). To sample this population, GfK targeted respondents in its principal panel who met our study criteria and reconfirmed their gun ownership and veteran status in the study-specific survey.

The study-specific survey had 3 stages: initial screening for gun ownership and veteran condition, the master survey conducted in April 2015 that included study-eligible respondents (gun owners and non-gun owners), and a vii-question supplemental survey in November 2015 targeting all gun owners identified in the April survey (pertinent to this report, questions related to the timing of their last firearm acquisition; an boosted 2 questions concerned firearm theft). To qualify for the main survey, a panel member must have been aged xviii years or older and was not currently serving on active duty in the U.S. War machine.

Data Collection

Survey pretesting occurred in March 2015, with administration of the last survey in April 2015. Potentially eligible panel members received an east-mail notifying them that a new survey was available for them to take. The electronic mail contained a direct link to the survey questionnaire; no login name or password was required. After 3 days, automated e-mail reminders were sent to all nonresponding console members in the sample. Participants completed the main survey in a median of 14 minutes.

The goal of GfK in structuring recruitment for the KP is a group that represents the U.S. developed population with respect to a broad gear up of geodemographic distributions equally well as subgroups of hard-to-reach adults (for example, those without a landline telephone or those who primarily speak Spanish). In selecting general population samples from the KP, GfK uses an equal probability of pick blueprint by weighting the entire KP to the benchmarks from the latest March supplement of the U.S. Census Agency's Current Population Survey (www.census.gov/cps/data/). The geodemographic dimensions used for weighting the entire KP typically include sexual activity, age, race, ethnicity, educational activity, demography region, household income, home buying status, metropolitan area, and Internet access. With these weights as the measure of size for each panel member, a probability proportional to size is used in the adjacent step to select study-specific samples. Application of the proportional-to-size methodology with the aforementioned measure of size values produces fully cocky-weighing KP samples, for which each sample member tin can carry a design weight of unity.

Study-Specific Poststratification Weights

Once the study sample was selected and fielded and all the survey data were edited and made final, design weights were adapted for whatsoever survey nonresponse (to the initial and to the supplemental survey) as well as whatever under- or overcoverage imposed by the report-specific sample pattern. For this study, the following strata of gun buying from weighted KP data and veteran status from the 2014 veteran supplemental survey of the Current Population Survey were used for the raking aligning of weights:

Sex, by historic period (18 to 29, 30 to 44, 45 to 59, 60 to 69, or =lxx years)

Census region (Northeast, Midwest, Due south, Westward), by metropolitan expanse (yep or no)

Sex, past veteran status (yeah or no)

Age (xviii to 29, 30 to 44, 45 to 59, 60 to 69, or =70 years), past veteran status (yes or no)

Race/Hispanic ethnicity (white/non-Hispanic, black/Non-Hispanic, other/Non-Hispanic, =ii races/Non-Hispanic, Hispanic), past veteran status (yeah or no)

Demography region (Northeast, Midwest, South, W), by veteran status (yes or no)

Metropolitan area (yes or no), by veteran status (yes or no)

Education (less than high school/high school, some college, bachelor or greater), by veteran condition (yes or no)

Household income (<$25 000, $25 000 to <$fifty 000, $50 000 to <$75 000, =$75 000 per twelvemonth), by veteran status (aye or no)

Net access (yep or no), by veteran status (yes or no)

Veteran serving years (<2, two to 3, 4 to 9, or =10 years)

Armed services branch (Air Strength, Regular army, Coast Guard/Marines/other, Navy)

Iterative proportional plumbing fixtures (raking) was performed to produce terminal weights aligned with respect to all strata simultaneously. In the last step, calculated weights were examined to place and, if necessary, trim outliers at the extreme upper and lower tails of the weight distribution. The resulting weights then were scaled to the sum of the total sample size of all eligible respondents.

We written report the study "completion charge per unit" for our survey on the ground of the formula developed by Callegaro and DiSogra (12) for response rates calculated applicable to Web panels. The study completion rate = ((Study Completes))/((Report Completes+Study Partial Completes)+(Study Refusals+Written report Noncontacts+Other Study Cases)).

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