Methods for estimating of the effectiveness of catheter ablation procedures to form lesions, and particular lesions which together form an ablation segment of an ablation line. Lesion effectiveness parameters are received, and effectiveness, optionally the joint effectiveness, of corresponding ablations (optionally planned, current, and/or already performed) is estimated. In some embodiments, estimating is based on use by computer circuitry of an estimator constructed based on observed associations between previously analyzed lesion effectiveness parameters, and observed lesion effectiveness. Additionally or alternatively, estimators may be constructed based on analytic functions. The estimator is used by application to the received lesion effectiveness parameters.