Data is such a funny word. It’s a plural, strictly. Part of me wants to use it that way, and show off, but a larger part of me always feels too self-conscious to do that. Thankfully, as Nathan Yau from FlowingData has discovered, the ‘rules’ around its use have been ‘officially’ relaxed.
Data is, sometimes
If you read data as singular then write it as such. For example, we already allow singular for ‘big data’. And we should for personal data too. An easy rule would be that if it can be used as a synonym for information then it should probably be singular — and if we are using it as economic data and mean figures, then we should stick to plural.