Topic analysis provides a set of themes or topics which define your text data. You can then use these themes to further segment the data and learn more about the segments of your data. Rather than randomly picking items and hoping they contain the information you need, topic analysis allows for a comprehensive overview of all of the text information. These segments can then drive further analysis of the data. Topic analysis can be used on hundreds, thousands or millions of text items. It provides information that no amount of human analysis can uncover. This link shows an example of content analysis of 387,000 food product reviews. Assuming someone could read and categorize each review every 20 seconds it would take about 90 days, working 24 hours a day, to categorize all of the 387,000 reviews. It takes us far, far less than 24 hours to perform a content analysis of the 387,000 reviews.