It turned out that Birdie Harms, a 64-year-old grandmother, part-time real-estate agent and longtime Republican was, by the Cruz campaign’s calculations, a “stoic traditionalist” — a conservative whose top concerns included President Obama’s use of executive orders on immigration.

Which meant that Stinemetz was instructed to talk to her in a tone that was “confident and warm and straight to the point” and ask about her concerns regarding the Obama administration’s positions on immigration, guns and other topics…

Cruz has largely built his program out of his Houston headquarters, where a team of statisticians and behavioral psychologists who subscribe to the burgeoning practice of “psychographic targeting” built their own version of a Myers-Briggs personality test. The test data is supplemented by recent issue surveys, and together they are used to categorize supporters, who then receive specially tailored messages, phone calls and visits. Micro-targeting of voters has been around for well over a decade, but the Cruz operation has deepened the intensity of the effort and the use of psychological data…

Another emerging tactic that the campaign has employed is “geo-fencing,” a technique that allows people to send messages to digital devices in narrow areas, such as a city block or single building.