The score impact is an indicator of whether each credit factor has a high, medium, or low impact on your credit score. The impact level shown is based on how the credit bureaus normally determine credit scores.
High impact credit factors include missed payments and credit utilization ratio which determine ~35% and ~30% of your overall credit score respectively. Derogatory marks (i.e. bankruptcy, consumer proposal, collections, judgments etc) also have a high impact as they can cause significant harm to your credit profile.
Medium impact credit factors include your average credit age, which determines ~15% of your overall credit score.
Low impact credit factors include credit inquiries and your total number of accounts, with each determining ~10% of your credit score.