American Jewish Population Project

FAQs

General

Who started AJPP and why?

The American Jewish Population Project (AJPP) was initiated with support from the Steinhardt Foundation for Jewish Life, under the leadership of Professor Leonard Saxe and Dr. Elizabeth Tighe. The goal was to provide a reliable, independent source of data on the US Jewish population that would inform understanding of American Jewry and be useful to researchers, policy makers, and others interested in Jewish Americans. From its inception, AJPP was designed to provide valid data which could be accessed by academic and lay users.

Unlike other demographic groups in the United States census, such as those defined by race, ethnicity, or economic status, there are no systematic sources of national data that can be used to describe the demographic characterstics of the US Jewish population. The separation of church and state in the United States prohibits the government from asking individuals to report their religious identity on a mandatory survey, such as the census. The absence of a question about religion in official statistics makes a description of the Jewish population exceptionally difficult. Given the lack of national-level data, different organizations have sought to collect their own systematic data. Typically, these expensive/costly single surveys are conducted once every decade. Absent any independent source with which to evaluate how representative these surveys are of the population as a whole, questions arise about the validity and generalizability of results.

AJPP goes beyond reliance on single surveys to synthesize all available sources of data, including surveys done by academic and public policy groups, and from specialized surveys of the American Jewish communities. These multiple sources of data, analyzed using state-of-the-art statistical techniques, are used to provide detailed population profiles of the US Jewish population. This resource is needed for the design and analysis of surveys of the Jewish population, and also provides an important resource to others who conduct Jewish population research.

What content is available on this site?

AJPP provides Jewish population estimates and detailed demographic profiles of Jewish adults for the nation, states, metropolitan areas and counties in the US. Demographic profiles include sex, age, educational attainment, and race/ethnicity. This content is provided on our interactive map, detailed tables, and reports and infographics.

Do I need to register for the site?

There is a lot of information available on the site without needing to register, including national estimates, infographics, and publications. Registering for the site will provide access to detailed (sub-national) estimates of the Jewish population.

How do I cite information from your website?

Current Population Estimates:

Tighe, E., Magidin de Kramer, R., Parmer, D., Kallista, D., Nussbaum, D., Seabrum, X., Mandell, J., & Saxe, L. (2020). American Jewish Population Project: Summary & Highlights 2020. In AJPP.Brandeis.edu. Retrieved [Date].

Detailed Table:

Data Table Name. In AJPP.Brandeis.edu. Retrieved [Date] from [Table url].

Map

Jewish Population in the United States 2020 [Map]. In AJPP.Brandeis.edu. Retrieved [Date] from [ajpp.brandeis.edu/map].

Can you provide custom tables or maps?

Don't see detailed tables you need on our data page? Want a customized map? We will work with you to provide comparisons you need. Send an email to ajpp@brandeis.edu.

How can we use your data in our study or community?

We have worked with several organizations and local Jewish communities to provide specialized analyses for their needs. Send an email to ajpp@brandeis.edu.

How do I contact you?

The best way to reach us is to email ajpp@brandeis.edu. You can also call us at 781-736-3958.

Technical

How do I register for the site?

To register for the site, please visit ajpp.brandeis.edu/register and complete the required fields. Click the box next to “I'm not a robot” and then press the submit button.

I registered for the site but did not receive a confirmation email.

1. If you did not receive a confirmation email after you registered, first check your Junk/Spam folders to make sure the email was not filtered for an email from ajpp@axismaps.io.

2. You may have entered your email address incorrectly during the registration. You can contact us at ajpp@brandeis.edu for additional help.

3. You may have entered your password incorrectly. Registered users can click here to change their password.

How do I use the map?

Click and drag anywhere on the map to pan the view, or use the scroll wheel to zoom in and out to different levels of detail. In the top right corner of the map, above the search bar, is an option to switch between State, Metro Area, and County Region views (requires login). When mousing over an area on the map (grouped depending on your selection), that area will be highlighted in yellow and a sidebar and tooltip will display information about the area's Jewish population. Clicking on an area will cause the sidebar to remain visible even when you move your mouse away from that area, displaying more detailed demographics, such as distributions of age, education, race, and gender. Holding down Shift and clicking on multiple areas will cause the sidebar to display population totals for those areas combined but will not display more detailed demographics.

The map page is not loading correctly.

This release of the map includes updates to the user interface and your computer may have stored a cookie from the previous version to speed up its loading. You can clear your browser's cookies or press Control+F5 (Cmd+Shift+R on a Mac) to completely reload the page and update the cookies. Depending on your browser, you might also need to clear your browsing history, other site data, as well as cached images and files.

How can I get a total over multiple areas on the map?

When users click to select a geographic area (state, county, or metropolitan area) a popup will display on the bottom of the map that instructs users to “Press Shift and click to view population totals for multiple areas.” Users can select as many areas as they wish. The total Jewish population and total adults who identify their religion as Jewish will appear in the sidebar display. Note, demographic and political data will not display when multiple areas are selected.

Our Research

Has your methodology been validated?

The AJPP method has been validated using data from Canada where results could be compared to the Canadian Census (Magidin de Kramer, Tighe, Saxe & Parmer, 2018). A comparison of three different methods for data synthesis showed that Bayesian Multilevel Regression with Poststratification (MRP) yielded estimates that were on par with the Canadian Census and out performed alternative methods. Another recent study (Claasen & Traunmüller, 2018) with data in the UK demonstrated that the MRP method yielded accurate estimates of the Jewish, Muslim, and Hindu populations over a 20-year period.

How do current estimates differ from previous years?

The present release provides the most recent estimates of the proportion of US adults who identify their religion as Jewish. The estimates are based on a set of independent samples of the U.S. adult population collected primarily across the years 2015-2019 and are adjusted to population estimates for the year 2020. Additional sources of data were used to provide total population estimates including Jewish children and those who might identify culturally, ethnically, or secularly as Jewish but do not identify as Jewish when asked about religion. These sources include the most recently available Jewish population survey conducted by Pew Research Center (2013) as well as local Jewish community studies conducted from 2010 to present. Total population estimates are available for all geographic areas (states, counties, and metropolitan areas). County groupings and metropolitan areas differ from the last release due to an increase in available sample size to estimate these areas (See Methodology).

Comparisons of the current estimates with previous estimates do not reflect population change. Differences in absolute values between current and previous estimates represent more the changes and improvements in methodology than they do changes in the distribution of the Jewish population within these areas.

Where does the data used in your estimates come from?

AJPP utilizes data from nationally representative surveys of the US population to produce estimates of the Jewish population in the contiguous United States, its states, metropolitan areas, and counties (or groups of counties). These include the General Social Survey, the American National Election Studies, as well as surveys and polls conducted by Pew Research Center and Gallup. For a complete list see AJPP Survey List.

Why are some areas so large while others are a single county?

Where there is sufficient sample size, counties are estimated singly. Many smaller counties have too few cases to be estimated on their own. We aim for a minimum sample size of approximately 1,000 cases in each geographic group. As we continue to develop models and add new sources of data, it may be possible to do custom analyses within these larger areas to obtain estimates for specific counties of interest.

Can you provide estimates for smaller areas, such as a city, town, or ZIP Code?

We collect data at lower levels of geography where it is available; however, surveys vary in the type of information that is available. If there is a particular area you are interested in, contact us! We're happy to talk about our data and to see what is possible.

Do you have data on other religious groups?

We collect data for all religiously defined groups represented in the surveys that are part of the data synthesis. This includes Protestant (denominations and subgroups within, including evangelical and mainline), Catholic, Mormon, and Muslim, as well as no religion and other religions. With the exception of Catholicism, religious representation varies considerably across surveys. For example, some surveys might not distinguish a general category of "Mormon" from the more specific LDS Church, or might only include general categories such as "Methodist," "Baptist," or "Lutheran" for Protestant denominations and ignore differences between specific denominations within those broad categories. We have not yet explored this variability or developed population models for these other groups. We have, however, begun to explore and model the large group who identify with no religion, which also varies across surveys in how it is assessed (atheist, agnostic, nothing in particular, etc.).

What other data do you collect?

A number of other variables are collected as part of the data synthesis project. The Jewish population models currently include only those variables related to model-based estimation of the population as a whole. These are male/female, age, educational attainment, and race/ethnicity, as well as geographic variables of state, counties, and metropolitan areas. Other variables collected as part of the project include: marital status, income, whether the respondent was born in the United States, political orientation, political affiliation, Jewish denomination (Orthodox, Conservative, Reform, etc.), religious service attendance, religious orientation (fundamentalist/evangelical), the importance of religion, household size, number of adults and children in the household, and community type (urban/suburban/rural; city, suburb, etc.). Surveys vary in which demographic data are included so sample sizes and numbers of samples vary for each analysis. A number of survey "meta-data" are recorded as well, such as date and day of the week the survey was conducted, incentives, and number of calls required to complete the survey. For a full list of variables see our Data Extract Codebook. The dataset also includes methodological characteristics of all surveys included in the synthesis, such as response rates, length of time in the field, survey shop, sampling methods, survey purpose, and questions used to assess religious affiliation. A full list of these survey level variables is included in our Survey Methods Codebook.

Why do other published estimates differ from yours?

Across county and metropolitan areas, estimates derived from the data synthesis vary in terms of how similar they are to population counts derived from other sources, such as those reported in the American Jewish Year Book (AJYB). There are many areas, small and large, where the data synthesis yields similar estimates to the Year Book. For as many areas where our model-based estimates are similar to those reported in the AJYB, there are many where the estimates are disparate. There are also cases where the AJPP estimates appear different from a local Jewish community study. This can be due to differences in geographic areas covered by AJPP and the local study as well as differences in definitions of who is Jewish. For further discussion of these issues, see our detailed research note, Why Do These Estimates Differ from Other Published Estimates, available to registered users.

What are the "Low" and "High" values?

The "Low" and "High" values represent the 95% credible intervals associated with each estimate. Credible intervals based on Bayesian analysis are similar in concept to confidence intervals reported in single surveys, which are often described in terms of the "margin of error." Both the credible intervals and the margin of error represent the degree of certainty associated with the estimate. They differ in how they are calculated and how they are interpreted. For example, if one estimates the proportion of U.S. adults who are Jewish to be 1.9% with a margin of error of 0.03, one would add or subtract this amount times some critical value to describe the variability in the estimate. For a 95% Confidence Interval, one would multiply the margin of error by 1.96, yielding a distribution that ranges from 1.84% at the lower end to 1.96% at the upper end. The confidence interval is based on the assumption that any sample drawn using the same sampling methods as those used in the particular survey of interest will yield a somewhat different estimate and a somewhat different range on that estimate. A 95% confidence interval means that, were one to repeat the sampling, one could expect 95% of the interval estimates to fall within the population parameter. In the Bayesian analysis, we are synthesizing data across repeated samples directly and are, therefore, reporting on results of the repeated samples themselves, rather than reporting on the assumption of repeated samples. For our national estimates, across all of the repeated independent samples, the estimated proportion of U.S. adults who identify as Jewish is 1.8%, with a 95% credible interval of 1.86% to 1.96%. This means that there is a 95% probability, based on the data and prior information, that the true population proportion of U.S. adults who identify their religion as Jewish is between this interval. For the demographic data, we have only included the point estimate on the map. For the full range of credible values associated with all of the detailed population estimates, see the detailed tables (requires registration).