Where do I find voterfile data to use in AdvoKit?

There is not a simple one-size fits all answer to this question. First of all, the availability and quality of inexpensive voter data is extremely variable by location The Help America Vote Act, passed in 2002, requires each state to have a computerized statewide voter registration system. In many states, this information available for free, or for a very low cost from either the Secretary of State, or local officials.

More to be written...

Maryland

In MD, you need to call each subdivision for the specifics, you can get contact information here: http://www.elections.state.md.us/citizens/county_boards.html.

To reach the State Board of Elections, call (800) 222-VOTE or SEP@elections.state.md.us.

New York City

in NYC you'd get this data from the department of city planning:
<a href="http://www.nyc.gov/html/dcp/html/bytes/applbyte.html"> http://www.nyc.gov/html/dcp/html/bytes/applbyte.html</a>

Check with your County Auditor

At least that's the case in Washington State. There is usually a nominal charge. For example, in Clark County, $35 will get you the entire voter file.