Correct term/word for bias in calculations? I ran an experiment recently and made several approximations in the calculations that led to the results being around 2 orders of magnitude less then the literature values.  I will be re-doing the calculations but in the meantime I need a word to describe what is wrong with this data set (ie what the effect was on the data by making the approximations).  

I thought saying the approximations resulted in a "statistical bias", or "analytical bias" might be right, but this is a little different that regular bias because the data is all fine and unbiased, its the approximations/calculations that are making the final results off by ~100x literature values.

I'm not sure if this is the right place to ask this, so if you think it belongs on the statistics stackexchange, please let me know.

If you're interest (or if it matters), the approximation was to ignore epithermal neutron capture in NAA analysis.
I believe the fundamental notion that you're looking for is a "systematic error in the data analysis". 

A "statistical bias" would imply some sort of sampling problem which doesn't seem to be the case from your description.

An "analytical bias" would imply a different/better laboratory technique which again doesn't seem to be the case. So although the overall results are biased, you don't need to redo the experiment itself but rather reanalyze the data using the proper calculations.