This R package implements the methods proposed in Imai, K. and Khanna, K. (2016). “Improving Ecological Inference by Predicting Individual Ethnicity from Voter Registration Record.” Political Analysis, Vol. 24, No. 2 (Spring), pp. 263-272. doi: 10.1093/pan/mpw001.
You can install the released version of wru from CRAN with:
Or you can install the development version of wru from GitHub with:
Here is a simple example that predicts the race/ethnicity of voters based only on their surnames.
library(wru)
future::plan(future::multisession)
predict_race(voter.file = voters, surname.only = TRUE)The above produces the following output, where the last five columns are probabilistic race/ethnicity predictions (e.g., pred.his is the probability of being Hispanic/Latino):
VoterID surname state CD county tract block age sex party PID place pred.whi pred.bla pred.his pred.asi pred.oth
1 Khanna NJ 12 021 004000 3001 29 0 Ind 0 74000 0.045110474 0.003067623 0.0068522723 0.860411906 0.084557725
2 Imai NJ 12 021 004501 1025 40 0 Dem 1 60900 0.052645440 0.001334812 0.0558160072 0.719376581 0.170827160
3 Rivera NY 12 061 004800 6001 33 0 Rep 2 51000 0.043285692 0.008204605 0.9136195794 0.024316883 0.010573240
4 Fifield NJ 12 021 004501 1025 27 0 Dem 1 60900 0.895405704 0.001911388 0.0337464844 0.011079323 0.057857101
5 Zhou NJ 12 021 004501 1025 28 1 Dem 1 60900 0.006572555 0.001298962 0.0005388581 0.982365594 0.009224032
6 Ratkovic NJ 12 021 004000 1025 35 0 Ind 0 60900 0.861236727 0.008212824 0.0095395642 0.011334635 0.109676251
7 Johnson NY 9 061 014900 4000 25 0 Dem 1 51000 0.543815322 0.344128607 0.0272403940 0.007405765 0.077409913
8 Lopez NJ 12 021 004501 1025 33 0 Rep 2 60900 0.038939877 0.004920643 0.9318797791 0.012154125 0.012105576
9 Wantchekon NJ 12 021 004501 1025 50 0 Rep 2 60900 0.330697188 0.194700665 0.4042849478 0.021379541 0.048937658
10 Morse DC 0 001 001301 3005 29 1 Rep 2 50000 0.866360147 0.044429853 0.0246568086 0.010219712 0.054333479In order to predict race/ethnicity based on surnames and geolocation, a user needs to provide a valid U.S. Census API key to access the census statistics. You can request a U.S. Census API key from the U.S. Census API key signup page. Once you have an API key, you can use the package to download relevant Census geographic data on demand and condition race/ethnicity predictions on geolocation (county, tract, block, or place).
First, you should save your census key to your .Rprofile or .Renviron. Below is an example procedure:
usethis::edit_r_environ()
# Edit the file with the following:
CENSUS_API_KEY=YourKey
# Save and close the file
# Restart your R sessionThe following example predicts the race/ethnicity of voters based on their surnames, census tract of residence (census.geo = "tract"), and party registration (party = "PID"). Note that a valid API key must be stored in a CENSUS_API_KEY environment variable or provided with the census.key argument in order for the function to download the relevant tract-level data.
VoterID surname state CD county tract block age sex party PID place pred.whi pred.bla pred.his pred.asi pred.oth
1 Khanna NJ 12 021 004000 3001 29 0 Ind 0 74000 0.021711601 0.0009552652 2.826779e-03 0.93364592 0.040860431
2 Imai NJ 12 021 004501 1025 40 0 Dem 1 60900 0.015364583 0.0002320815 9.020240e-03 0.90245186 0.072931231
3 Rivera NY 12 061 004800 6001 33 0 Rep 2 51000 0.092415538 0.0047099965 7.860806e-01 0.09924761 0.017546300
4 Fifield NJ 12 021 004501 1025 27 0 Dem 1 60900 0.854810748 0.0010870744 1.783931e-02 0.04546436 0.080798514
5 Zhou NJ 12 021 004501 1025 28 1 Dem 1 60900 0.001548762 0.0001823506 7.031116e-05 0.99501901 0.003179566
6 Ratkovic NJ 12 021 004000 1025 35 0 Ind 0 60900 0.852374629 0.0052590592 8.092435e-03 0.02529163 0.108982246
7 Johnson NY 9 061 014900 4000 25 0 Dem 1 51000 0.831282563 0.0613242553 1.059715e-02 0.01602557 0.080770461
8 Lopez NJ 12 021 004501 1025 33 0 Rep 2 60900 0.062022518 0.0046691402 8.218906e-01 0.08321206 0.028205698
9 Wantchekon NJ 12 021 004501 1025 50 0 Rep 2 60900 0.396500218 0.1390722877 2.684107e-01 0.11018413 0.085832686
10 Morse DC 0 001 001301 3005 29 1 Rep 2 50000 0.861168219 0.0498449102 1.131154e-02 0.01633532 0.061340015In predict_race(), the census.geo options are “county”, “tract”, “block” and “place”. Here is an example of prediction based on census statistics collected at the level of “place”:
VoterID surname state CD county tract block age sex party PID place pred.whi pred.bla pred.his pred.asi pred.oth
1 Khanna NJ 12 021 004000 3001 29 0 Ind 0 74000 0.042146148 0.0620484276 9.502254e-02 0.55109761 0.249685278
2 Imai NJ 12 021 004501 1025 40 0 Dem 1 60900 0.018140322 0.0002204255 1.026018e-02 0.90710894 0.064270133
3 Rivera NY 12 061 004800 6001 33 0 Rep 2 51000 0.015528660 0.0092292671 9.266893e-01 0.04182290 0.006729825
4 Fifield NJ 12 021 004501 1025 27 0 Dem 1 60900 0.879537890 0.0008997896 1.768379e-02 0.03982601 0.062052518
5 Zhou NJ 12 021 004501 1025 28 1 Dem 1 60900 0.001819394 0.0001723242 7.957542e-05 0.99514078 0.002787926
6 Ratkovic NJ 12 021 004000 1025 35 0 Ind 0 60900 0.834942701 0.0038157857 4.933723e-03 0.04021245 0.116095337
7 Johnson NY 9 061 014900 4000 25 0 Dem 1 51000 0.290386744 0.5761904554 4.112613e-02 0.01895885 0.073337820
8 Lopez NJ 12 021 004501 1025 33 0 Rep 2 60900 0.065321588 0.0039558641 8.339387e-01 0.07461133 0.022172551
9 Wantchekon NJ 12 021 004501 1025 50 0 Rep 2 60900 0.428723819 0.1209683869 2.796062e-01 0.10142953 0.069272098
10 Morse DC 0 001 001301 3005 29 1 Rep 2 50000 0.716211008 0.1899554127 1.867133e-02 0.01025241 0.064909839It is also possible to pre-download Census geographic data, which can save time when running predict_race(). The example dataset voters includes people in DC, NJ, and NY. The following example subsets voters in DC and NJ, and then uses get_census_data() to download census geographic data in these two states (a valid API key must be stored in a CENSUS_API_KEY environment variable or provided with the key argument). Census data is assigned to an object named census.dc.nj. The predict_race() statement predicts the race/ethnicity of voters in DC and NJ using the pre-downloaded census data (census.data = census.dc.nj). This example conditions race/ethnicity predictions on voters’ surnames, block of residence (census.geo = "block"), age (age = TRUE), and party registration (party = "PID").
Please note that the input parameters age and sex must have the same values in get_census_data() and predict_race(), i.e., TRUE in both or FALSE in both. In this case, predictions are conditioned on age but not sex, so age = TRUE and sex = FALSE in both the get_census_data() and predict_race() statements.
library(wru)
voters.dc.nj <- voters[voters$state %in% c("DC", "NJ"), ]
census.dc.nj <- get_census_data(state = c("DC", "NJ"), age = TRUE, sex = FALSE)
predict_race(voter.file = voters.dc.nj, census.geo = "block", census.data = census.dc.nj, age = TRUE, sex = FALSE, party = "PID")This produces the same result as the following statement, which downloads census data during evaluation rather than using pre-downloaded data:
Using pre-downloaded Census data may be useful for the following reasons:
predict_race() if the relevant census data has already been saved;predict_race() may not have internet access;Downloading data using get_census_data() may take a long time, especially in large states or when using small geographic levels. If block-level census data is not required, downloading census data at the tract level will save time. Similarly, if tract-level data is not required, county-level data may be specified in order to save time.
library(wru)
voters.dc.nj <- voters[voters$state %in% c("DC", "NJ"), ]
census.dc.nj2 <- get_census_data(state = c("DC", "NJ"), age = TRUE, sex = FALSE, census.geo = "tract")
predict_race(voter.file = voters.dc.nj, census.geo = "tract", census.data = census.dc.nj2, party = "PID", age = TRUE, sex = FALSE)
predict_race(voter.file = voters.dc.nj, census.geo = "county", census.data = census.dc.nj2, age = TRUE, sex = FALSE) # Pr(Race | Surname, County)
predict_race(voter.file = voters.dc.nj, census.geo = "tract", census.data = census.dc.nj2, age = TRUE, sex = FALSE) # Pr(Race | Surname, Tract)
predict_race(voter.file = voters.dc.nj, census.geo = "county", census.data = census.dc.nj2, party = "PID", age = TRUE, sex = FALSE) # Pr(Race | Surname, County, Party)
predict_race(voter.file = voters.dc.nj, census.geo = "tract", census.data = census.dc.nj2, party = "PID", age = TRUE, sex = FALSE) # Pr(Race | Surname, Tract, Party)You can use census_geo_api() to manually construct a census object. The example below creates a census object with county-level and tract-level data in DC and NJ, while avoiding downloading block-level data. Note that the state argument requires a vector of two-letter state abbreviations.
census.dc.nj3 = list()
county.dc <- census_geo_api(state = "DC", geo = "county", age = TRUE, sex = FALSE)
tract.dc <- census_geo_api(state = "DC", geo = "tract", age = TRUE, sex = FALSE)
census.dc.nj3[["DC"]] <- list(state = "DC", county = county.dc, tract = tract.dc, age = TRUE, sex = FALSE)
tract.nj <- census_geo_api(state = "NJ", geo = "tract", age = TRUE, sex = FALSE)
county.nj <- census_geo_api(state = "NJ", geo = "county", age = TRUE, sex = FALSE)
census.dc.nj3[["NJ"]] <- list(state = "NJ", county = county.nj, tract = tract.nj, age = TRUE, sex = FALSE)Note: The age and sex parameters must be consistent when creating the Census object and using that Census object in the predict_race function. If one of these parameters is TRUE in the Census object, it must also be TRUE in the predict_race function.
After saving the data in censusObj2 above, we can condition race/ethnicity predictions on different combinations of input variables, without having to re-download the relevant Census data.
predict_race(voter.file = voters.dc.nj, census.geo = "county", census.data = census.dc.nj3, age = TRUE, sex = FALSE) # Pr(Race | Surname, County)
predict_race(voter.file = voters.dc.nj, census.geo = "tract", census.data = census.dc.nj3, age = TRUE, sex = FALSE) # Pr(Race | Surname, Tract)
predict_race(voter.file = voters.dc.nj, census.geo = "county", census.data = census.dc.nj3, party = "PID", age = TRUE, sex = FALSE) # Pr(Race | Surname, County, Party)
predict_race(voter.file = voters.dc.nj, census.geo = "tract", census.data = census.dc.nj3, party = "PID", age = TRUE, sex = FALSE) # Pr(Race | Surname, Tract, Party)For larger scale imputations, garbage collection can become a problem and your machine(s) can quickly run out of memory (RAM). We recommended using the future.callr::callr plan instead of future::multisession. The callr plan instantiates a new session at every iteration of your parallel loop or map. Although this has the negative effect of creating more overhead, it also clears sticky memory elements that can grow to eventual system failure when using multisession. You end up with a process that is more stable, but slightly slower.
This package uses the Census Bureau Data API but is not endorsed or certified by the Census Bureau.
U.S. Census Bureau (2021, October 8). Decennial Census API. Census.gov. Retrieved from https://www.census.gov/data/developers/data-sets/decennial-census.html
