According to Jitta Score calculation, popularity, size or project plan of a company isn't taken into account. Hence, Jitta Score will perfectly reflect only the business performance as Warren Buffett said, “In the business world, the rear view mirror is always clearer than the windshield.”
For the companies with low Jitta Score, you can find their reasons from Jitta Signs and Jitta Factors. Jitta Signs can quickly indicate the strengths and weaknesses from a company’s financial statements and Jitta Factors show the quality of a business which analyze from the five key elements of a business-- Growth Opportunity, Recent Business Performance, Financial Strength, Return to Shareholders, Competitive Advantage.
So that the causes of companies with low Jitta Score might come from a bad management of the company's profit, a high long term debt, an uncontrollable price/cost of products, a flat growth opportunity and so on.
Like Berkshire Hathaway-- Warren Buffett's company has a Jitta Score of 5 to 6. It is considered as a fair business because the size of the business is quite large. Therefore, investing in a smaller business which has a higher growth opportunity provides better return than investing in Berkshire Hathaway. The returns could be over 100% if you invest in Berkshire during 2008 to 2015 period. However, if you buy stock which has a higher Jitta Score you will increase your returns by 500% due to a rocketing growth.