What's trending on Twitter isn't always an accurate reflection of public opinion. A large number of tweets may indicate public interest in a topic or event, but not a full picture of what the public thinks.
This isn't surprising. Twitter is a self-selected social media tool. The body of tweets doesn't need to reflect the demographics of a community, state or constituency. People who tweet on a topic may be more liberal, more conservative, richer or poorer than the public at large. Comments have value, but can't be rendered in quantitative terms the same as public opinion polling.
Quality public opinion polling is centered on a representative sample of who is interviewed. That assures the findings have credibility as a reliable reflection of the group being surveyed, with a slight margin of error.
The breadth and depth of the digital revolution may tempt some to see social media platforms as mirrors of public opinion. They certainly are reflections, but not ones you can totally rely upon to make decisions on messaging, trustworthy spokespeople and effective communication channels. A solid poll is a much better instrument for that.
Twitter conversations can be valuable to assess. For example, tweets can show the emotional charge in an issue or how an issue activates a particular group. The compressed format helps people distill what they feel to a few words, which in effect become sound bites. Tweets also can show the range of reactions.
In the world of measurement, there is room for evaluation of platforms such as Twitter. But it is important to recognize the right tool for the job. When you need an accurate picture of how a constituency views an issue, a poll with a representative sample is a much better choice.