It is... 'Information is missing'. Technically, it should be 'data are missing' but it is rarely used as a plural noun so 'data is missing' would be fine. Data is the plural of datum but nobody ever says datum. Hope that helps, Chris

"Information" is uncountable in English, so you treat it as "it". Some information is missing. A lot of information is missing. A piece of information is missing. (Yes, you can change this to "Many pieces... are...") It's a lot trickier with "data", as this is technically the plural form of "datum". You would definitely make this distinction in a technical/academic context. I had a quick check of how often "is/are" is used with "data", and "data are" is still use much more often than "data is", although "data is" seems quite acceptable. I'd do a search on the phrase you want to use, to see how other writers have managed it.