In startup investments like this one the media basically make a simple factor of the percentage an investor gains and the price he's paying for it. There is no value to that number besides nice newspaper titles.
Real evaluation is the same as for any other company, however in a private company you have less data to go with, the data can't be relied upon as much (since the source is mostly the company itself), and all of these risks get increased by the company being relatively new and not profitable yet. In exchange for the risk investors hope to gain similar growth of company value after they purchased their shares. Therefore most investors mostly look for factors that show huge growth chances, instead of looking at traditional health factors.
Real evaluation is the same as for any other company, however in a private company you have less data to go with, the data can't be relied upon as much (since the source is mostly the company itself), and all of these risks get increased by the company being relatively new and not profitable yet. In exchange for the risk investors hope to gain similar growth of company value after they purchased their shares. Therefore most investors mostly look for factors that show huge growth chances, instead of looking at traditional health factors.