The most popular type of credit score among lenders is the FICO score. More than 80% of the banks in the United States use this type of score. Usually, you will have a separate and distinct score from each of the three main credit bureaus, which are Equifax, TransUnion, and Experian. These scores are taken strictly from the information in the file that each credit bureau keeps on you. When the information that is saved in your credit file changes, so does your FICO score.
Maybe you went car shopping one weekend and had several dealers check to see if you qualified for a car on their lot you were interested in. Maybe you took your bank up on an offer for a new bank card. Maybe you applied at two department stores for credit cards while you were at the mall. Or, maybe you are trying to buy a new home. All of these things could change your FICO score.