"We generally have not awarded Pinocchios when researching how politicians speak about family myths and stories."

"We also do not play gotcha when a politician flubs a talking point they have gotten correct on other occasions. Biden went too far on Tuesday when he described his great-grandfather as a 'coal miner,' but during the presidential campaign he correctly labeled him a mining engineer. So this is not a repeat of 1988, when Biden repeatedly lifted lines from a British politician’s speech and falsely said he had ancestors who worked 12 hours underground." 

Writes Glenn Kessler at The Washington Post, in the Fact Checker piece, "Biden’s claim that his ‘great-grandpop’ was a coal miner."