Tex. Election Code § 18.0681

(a) The secretary of state shall periodically compare the information regarding voters maintained as part of the statewide computerized voter registration list to determine whether any voters have more than one voter registration record on file.

(b) The secretary of state shall by rule determine what information combinations identified as common to more than one registration record constitute a weak match or a strong match in order to:

(1) produce the least possible impact on Texas voters; and

(2) fulfill its responsibility to manage the voter rolls.

(c) The secretary of state may not determine that a voter has more than one registration record based on a weak match. The secretary of state may inform the county of the voter's residence that a weak match exists.

(d) If the secretary of state determines that a voter on the registration list has more than one registration record on file based on a strong match, the secretary shall send notice of the determination to the voter registrar of the county with the oldest registration record in which the voter is registered to vote. If the voter records identified are:

(1) located in the same county, the voter registrar may merge the records following a determination that each record belongs to the same voter using the procedure for the correction of registration records under Section 15.022; or

(2) located in more than one county, the registrar of the county with the oldest record may deliver a written confirmation notice in accordance with Section 15.051 or cancel the registration of the voter in accordance with Section 16.031(a)(1), provided that the voter's record in the county with the newest registration record is not on the suspense list.