I would consider myself a journeyman data scientist.  Like most (I think), I made my first charts and did my first aggregations in high school and college, using Excel.  As I went through college, grad school and ~7 years of work experience, I quickly picked up what I consider to be more advanced tools, like SQL, R, Python, Hadoop, LaTeX, etc.We are interviewing for a data scientist position and one candidate advertises himself as a senior data scientist (a very buzzy term these days) with 15+ years experience.  When asked what his preferred toolset was, he responded that it was Excel.I took this as evidence that he was not as experienced as his resume would claim, but wasn't sure.  After all, just because it's not my preferred tool, doesn't mean it's not other people's. Do experienced data scientists use Excel?  Can you assume a lack of experience from someone who does primarily use Excel?
Do data scientists use Excel?
tools;career;excel
Most non-technical people often use Excel as a database replacement. I think that's wrong but tolerable. However, someone who is supposedly experienced in data analysis simply can not use Excel as his main tool (excluding the obvious task of looking at the data for the first time). That's because Excel was never intended for that kind of analysis and as a consequence of this, it is incredibly easy to make mistakes in Excel (that's not to say that it is not incredibly easy to make another type of mistakes when using other tools, but Excel aggravates the situation even more.)To summarize what Excel doesn't have and is a must for any analysis:Reproducibility. A data analysis needs to be reproducible.Version control. Good for collaboration and also good for reproducibility. Instead of using xls, use csv (still very complex and has lots of edge cases, but csv parsers are fairly good nowadays.) Testing. If you don't have tests, your code is broken. If your code is broken, your analysis is worse than useless. Maintainability.Accuracy. Numerical accuracy, accurate date parsing, among others are really lacking in Excel.More resources:European Spreadsheet Risks Interest Group - Horror StoriesYou shouldnt use a spreadsheet for important work (I mean it)Microsoft's Excel Might Be The Most Dangerous Software On The PlanetDestroy Your Data Using Excel With This One Weird Trick!Excel spreadsheets are hard to get right