Cost-effective: giving the best possible profit or benefits in comparison with the money that is spent. Rentable. E.g. a cost-effective way to fight crime.
Biased: /ˈbaɪəst/ having a tendency to show favour towards or against one group of people or one opinion for personal reasons; making unfair judgements.Partial. Tendencioso. E.g. biased information/sources/press reports. A biased jury/witness.
Unbiased: fair and not influenced by your own or somebody else's opinions, desires, etc. Impartial. Objetivo, imparcial. E.g. unbiased advice. An unbiased judge.
Misleading: giving the wrong idea or impression and making you believe something that is not true. Engañoso. E.g. misleading information/advertisements. It would be seriously misleading to suggest that television has no effect on children.