Most polling firms possess reams of data, from which they try to generate sound bites of polling results that are picked up by the media.
Polling firms try to secure as much media attention as possible while holding back much of the details; they want sell access to their data for big money. So while one organization might offer online access to a 60 page report, another may offer nothing more than a handful of sentences centering around one piece of data.
Polling firms determines how much information is released to their paying clients, and how much is released free of cost to the public or to academic researchers. The different levels of disclosure are based more on the whims of each polling group rather than a consistent formulaic decision.
Keep in mind that much of the data that has been collected is hidden behind paywalls and may not be publicly available.
Non-Profit Polling Groups & Firms
For-Profit Polling Groups & Firms