How can third-party companies predict future successful sports merchandise?

If the third party has access to the statistics of using current merchindise in the past until now it can predict with certain degree of probability whether this merchandise will be successfull in the future.

When it comes to the new merchandise. A company usualy rely on the statistic of similar merchandise by taking into account a brand name, quality, functianality and price of a new merchandise.

If it is completely new invented merchindise, company still evaluate brand name, quality, functianality and price pluss it look if there is a potential market for this new product.