EPEC has compared the changes to two purchased full versions of the VA Registered Voter List (RVL) to the content of the Monthly Update Service (MUS) data covering the same temporal period. Of the ID numbers that were added to the RVL, 3,613 (or 1.0589% of total additions) never appear anywhere in the MUS files covering the same temporal period. Of the ID numbers that were removed from the RVL, 3,355 (or 2.4096% total removals) never appear anywhere in the MUS files covering the same temporal period.
Since mid 2023 EPEC has been purchasing, processing and archiving copies of both the full Registered Voter List (RVL) and the Monthly Update Service (MUS) files which gives the UPDATE, ADD or CANCEL transactions to the voter list throughout the year.
Once a baseline RVL is established, the MUS files can be used to update that baseline in order to keep the list current. That should be all one needs to keep an accurate dataset of the registered voter list using monthly updates … except there is a catch … the MUS for some reason doesn’t quite capture all of the changes that are occurring in the voter list. In fact, we see about 1-2.5% of the ADD or CANCEL transactions between each RVL snapshot are not reflected by any corresponding entries in the MUS.
All of the changes that are made between two different RVL baseline snapshots should be able to be observed in the corresponding MUS files that cover the same time period, and vice versa. The MUS has transaction logs accounting for new registrants, for registrants who move, for removing deceased individuals, for individuals that have had a change in their felon status, for individuals who are determined non-citizen, for administrative updates and correction, etc. So, in theory, it should be able to be a complete record. However, over the course of working with the VA data files, every so often we have noticed that some transactions seem to be unaccounted for. Therefore, once we had enough data compiled, we decided to test just how well the MUS data actually explains the changes we see between between two baseline RVL files.
Method:
For this experiment, we used full RVL snapshots purchased from VA Department of Elections (ELECT) on 2023-06-30 and 2024-08-29, and all of the monthly MUS distributions covering the entire time period in between.
Using the voter ID number field that is present in all datasets, we first determine which ID numbers were added to the 2024 RVL dataset, and which ID numbers were deleted from the 2023 RVL data. We then checked to see how many of those ID numbers appear in any of the MUS data files, for any reason.
Note that this data was processed statewide, such that registrants moving between localities within the state should not affect the total number of computed additions or removals, as the ID numbers should still be present in the datasets, although corresponding locality information may have changed.
Results:
The breakdown of the number of changes that were present in the MUS file over the time period of the RVL snapshots (2023-06-30 through 2024-08-29) is given in Figure 1 below. The MUS data was deduplicated and truncated to only consider transactions with TRANSACTION date information between the dates associated with the RVL datasets. The bars in Figure 1 are logarithmically scaled in the y-axis, with the x-axis representing the NVRAReasonCode given for each transaction in the MUS. The bars are color coded by transaction type. As there are duplicates and oversampling within the collection of MUS files, only the latest transactions for each uniquely identified ID number was utilized to generate the plot. As can be seen from the various categories along the x-axis of this plot, the data in the MUS logs should be sufficient to capture all of the transactions with the RVL.
Figure 1: Breakdown of MUS transactions between 2023-06-30 and 2024-08-29
Direct Inspection of the RVL Snapshots:
Performing a simple set-difference between the elements of the unique ID numbers present in the 2023-06-30 RVL data vs the 2024-08-29 RVL data shows that there were 341,191 unique ID’s added, and 139,232 removed between the two datasets.
Of the ID numbers that were ADDED between the raw RVL snapshots, 3,613 (or 1.0589%) never appear anywhere in the MUS files covering the same temporal period.
Of the 3,613 ID numbers that were ADDED between the raw RVL snapshots, and that don’t appear in the MUS record, 537 (or 14.863%) have at least one entry in the Voter History List (VHL) data the EPEC has been collecting and archiving.
Of the ID numbers that were REMOVED between the raw RVL snapshots, 3,355 (or 2.4096%) never appear anywhere in the MUS files covering the same temporal period.
Of the 3,355 ID numbers that were REMOVED between the raw RVL snapshots, and that don’t appear in the MUS record, 2,011 (or 59.94%) have at least one entry in the VHL data the EPEC has been collecting and archiving.
Using the MUS-Adjusted RVL baseline
If we ignore the 2024-08-29 dataset, and instead directly apply the transactions in the MUS datafiles to the 2023-06-30 dataset in order to create a new RVL list, we would end up with 342,888 Additions, and 137,849 removals respectively to unique voter ID numbers. We see 1,697 more (342,888-341,191=1697) additions when trying to directly apply the MUS than when directly comparing RVL snapshots, and 1,383 less (139,232-137,849=1393) removals. Keep in mind these discrepancies are in addition to the 3,613 and 3,355 discrepancies using the RVL snapshot baselines, as the ID numbers in each set are unique. So the total number of discrepancies is 3,613 + 3,355 + 1,697 + 1,383 = 10,048 records.
Summary of these results:
Num_Added: 341191
Num_Added_not_in_MUS: 3613
Pct_Added_not_in_MUS: 1.0589
Num_Added_not_in_MUS_wVHL: 537
Num_Removed: 139232
Num_Removed_not_in_MUS: 3355
Pct_Removed_not_in_MUS: 2.4096
Num_Removed_not_in_MUS_wVHL: 2011
MUS_Num_Deletions: 137849
MUS_Num_Additions: 342888
MUS_Num_Updates: 946248
NUS_Num_NOOP_ADD: 651
NUS_Num_NOOP_MODIFY: 334282Discussion:
We do not understand yet the origin of these discrepancies, it could be a coding error on the part of the developers of the VERIS system, or it could be that there is a category of data adjustments that is not adequately reflected in the RVL or MUS data products. The RVL snapshots are supposed to be the authoritative record of the voter registration data, and the MUS data updates are supposed to capture all of the transactional changes to said registration records.
Regardless of the cause of the discrepancy, the fact remains that there are a small number of transactions and changes to the voter record that are unobservable. They are, in effect, “dark” transactions in the voter registration data that cannot be observed, validated or verified.