6. A computer-implemented method of generating phrase categories for interactions recorded at a call center, the method comprising: displaying, using a computer processor, a graphical user interface to a user, the graphical user interface comprising: an input area for the user to input a base category and one or more phrases, for analysis of the base category, and an input area for the user to input a candidate phrase for analysis; obtaining via user input the base category; obtaining via user input the candidate phrase; defining a reference phrase category that includes one or more phrases; generating, using the computer processor, a base trend of the reference phrase category, wherein a trend of a category is defined by a set of values representing a number of recorded interactions that are specific to the call center, in a respective set of time units, that include at least one phrase included in the category, each recorded interaction comprising a text recording of a conversational exchange, wherein at least some of the text recordings are produced via a speech to text process applied to an audio recording; generating, using the computer processor, an accuracy value for the candidate phrase by determining a correlation between: a first candidate trend determined based on the frequency of appearance of the candidate phrase in the set of recorded interactions determined using a first accuracy value; and a second candidate trend determined based on the frequency of appearance of the candidate phrase in the set of recorded interactions determined using a second accuracy value; generating, using the computer processor, a candidate trend of the candidate phrase based on a frequency of appearance of the candidate phrase in the set of recorded interactions determined using the generated accuracy value, each candidate trend comprising a series of numbers of interactions per time unit for each of a series of time units; calculating, using the computer processor, a correlation level based on the candidate trend and the base trend; and if the correlation level is greater than a threshold level then, using the computer processor, including the candidate phrase in the base category; and displaying to a user the candidate phrase.
7. The method of claim 6 , comprising: iteratively selecting a candidate phrase from a set of candidate phrases, and, for each selected candidate phrase: generating a candidate trend for the selected candidate phrase, calculating a correlation value for the selected candidate phrase, and if the correlation value is greater than a threshold level then including the selected candidate phrase in the base category.