Many researchers wish to target participants from specific states or regions of the United States like the Northeast or the West. The problem they often encounter is that using MTurk's Geographic Qualification to specify a particular state is often not adequate to ensure participants actually reside in the specified state.
The state MTurk believes a worker is in may be wrong because workers sometimes move after setting up their MTurk account. In addition, it has been reported that MTurk may use the worker's bank location to identify which state the worker is in, a method that causes problems when workers use a bank that does not match their state of residency. Internal quality tests at TurkPrime have shown that up to 25% of workers are identified by MTurk's Geographic Qualification as being in a state that does not match the state associated with the worker's IP address.
To ensure workers actually reside in the state or US region you want to target, you can use TurkPrime's Pro Feature to verify location by IP address and the US Region selector. Both of these features will only qualify workers whose IP address has been verified as matching the state or region you select. All other workers will be disqualified from taking the study.
In addition, to run regionally targeted studies, TurkPrime now includes a region selector which automatically includes IP state verification to ensure quality results.