Why did I not get the results that I expected?

The quality or quantity of the questioned material may be such that no conclusion could be rendered.

There may be so little comparability between the known and the questioned that an examination could not be performed.

Outside influences (drugs, illness, disguise, etc. ) may have affected the handwriting to the degree that no examination could  be performed.

The Certificate of Analysis will normally include explanations of any significant limiting factors encountered during the examination.