Variance Analysis assess the magnitude of variation from the original planned work.

Common sense –
Variance means fluctuations i.e. deviations
Analysis means study or finding the root cause or investigating

Using common sense do you think Variance Analysis can be an input to any process?

Of course NO, it can be tool/techniques. Also, the result of variance analysis can be part of some documentation updates (output).

Read this article for more information on it:
http://project-management-knowledge.com/definitions/v/variance-analysis/

Saket, PMP