1. A method of identifying a quantitation cycle (C q ) for a PCR amplification reaction characterized by a plurality of data points each including a cycle value associated with a PCR cycle and a product value associated with a PCR product, the method comprising: a) fitting a plurality of line segments to the data points associated with the PCR amplification reaction; b) identifying a baseline of the PCR amplification reaction; c) identifying a reaction segment associated with an exponential region of the PCR amplification reaction as a first subset of the plurality of line segments having a slope not less than a steepness criteria; d) fitting a reaction line to the data points associated with the reaction segment; and e) extrapolating the reaction line to intersect the baseline at the C q .