##### Considering Context

Distinctive context can appear on either side of a transcription error. The surrounding context of the transcription error should be taken into account when developing substitution rules because that context mitigates the potential risk of false positives.

For example, the term “ACH” appears frequently in the context of banking and moving money (payments, direct deposits). “ACH” is an important topic and categorization term for analysis and should not be ignored. When spoken quickly, "ACH" can sound very similar to "KCH". This is especially true when audio is damaged by lossy compression, poor cellular reception, or loud background noise.

A substitution rule like "k c h : /ACH/" is too general and would likely introduce false postives when people spell out names that include the letters "k c h". Rather than create a contextless substitution rule like "k c h : /ACH/", search the transcripts for different instances of "k c h" and add the necessary context to your rules. The following example illustrates a few different substitution rules with different contexts. However, they are all meant to correct different instances of the same transcription error.

electronic k c h : electronic /ACH/
k c h debit : /ACH/ debit
k c h transfer : /ACH/ transfer
k c h payment : /ACH/ payment

The substitution rules above will work to correct a phrase such as, "make an electronic k c h payment", where matching context could occur on either side.