Hold the Phone: A Big-Data Conundrum

[Commentary] Yes, phones feel slower over time as they hold more software and as our expectations of speed increase. But the spikes show that the feeling doesn’t grow gradually; it comes on suddenly in the days after a new phone is released. Yet that’s all it shows: People suddenly feel that their phone is slowing down. The data doesn’t show our iPhones actually became slower.

The important distinction is of intent. In the benign explanation, a slowdown of old phones is not a specific goal, but merely a side effect of optimizing the operating system for newer hardware. Data on search frequency would not allow us to infer intent. No matter how suggestive, this data alone doesn’t allow you to determine conclusively whether my phone is actually slower and, if so, why.

[Mullainathan is a professor of economics at Harvard]