It’s kind of like using different scales to measure your weight – you’re going to get slight variations between scales but consistency within a scale. As a result, when researchers are looking to see if their analyses are accurate across the data sets, absent large discrepancies, what they’re looking for is general directional trends. It matters less if NASA says that 2016 was one degree Celsius warmer and the Met, for example, said it was 1.2 degrees Celsius warmer. What matters is that both agencies agree that the temperature is warming. And in analyzing temperature data from over the past 130 plus years, all of the agencies have found that generally, the climate is heating up.