Laura Doull was a patient of Anna C. Foster (D), a nurse practitioner, and her supervisor, Dr. Richard J. Miller (D), an internist, owned the medical practice. In August 2008, Doull had an appointment with Foster (D) regarding perimenopause-related symptoms. Foster (D) prescribed Doull a topically applied, naturally derived progesterone cream to treat the symptoms. Foster (D) did not document any conversation that she had with Doull about the risks and benefits of, or the alternatives to, the progesterone cream, but she did testify that they discussed alternatives to it. Foster (D) did not discuss the possibility with Doull that the progesterone cream could cause blood clots because she did not consider this to be a risk. Doull used the progesterone cream through the spring of 2011. Earlier that spring, Doull had visited the practice on three separate occasions to complain about shortness of breath. Doull met with Foster (D) on each visit, and Foster (D) performed a physical examination of Doull each time. Doull had a history of asthma and allergies. At the spring 2011 visits, Foster (D) diagnosed Doull's shortness of breath as a symptom of some combination of these long-standing conditions. Miller (D) did not examine Doull during any of these visits. In May 2011, Doull had a “seizure-like event” and was transported to the hospital and diagnosed with a pulmonary embolism. A pulmonary embolism may cause shortness of breath as well as chronic thromboembolic pulmonary hypertension (CTEPH), a rare disease where pressure in the pulmonary artery increases and causes the heart to fail. A lung scan revealed that blood clots in Doull's lungs were chronic. Doull underwent surgery in an attempt to remove the blockage from her lungs, but the procedure proved unsuccessful. Medications failed to abate the disease. In 2015, Doull died from complications arising from CTEPH. She was forty-three years old. Doull and various family members (Ps) commenced this suit against Ds, claiming negligence, failure to obtain informed consent, and loss of consortium. Ps argued that Ds failed to obtain informed consent that Foster (D) failed to diagnose Doull's pulmonary embolism during the spring 2011 visits, and that Miller (D) failed to supervise Foster (D) adequately during all relevant times. Ps' expert witness, Dr. Paul Genecin, testified that natural progesterone was not any safer than synthetic derivations of the hormone and that the cream likely caused Doull to develop blood clots. He also testified that Foster (D) had failed to investigate adequately Doull's shortness of breath complaints during the spring 2011 visits. He testified that a proper diagnosis could have prevented the onset of CTEPH and that Miller's failure to supervise Foster's (D) actions constituted a breach of the duty of care. Ds' expert witness, Dr. Nicholas S. Hill testified that there was “no evidence anywhere that indicates that progesterone cream applied to the skin increases the risk of clotting.” Hill testified that by the time Doull was diagnosed with CTEPH in May 2011, the disease “had been going on for a long time, probably months at least.” According to Hill, the chronic nature of Doull's blood clots meant that her outcome would have remained the same had Foster (D) diagnosed her with the disease during the spring of 2011. The jury was instructed on but for causation. The jury found Ds had not failed to acquire informed consent from Doull with respect to the progesterone cream; that Foster (D) negligently failed to diagnose Doull's pulmonary embolism; but that this negligence was not the cause of either the harms suffered by Doull after her seizure-like event in 2011 or her death in 2015. The jury found that Miller (D) had been negligent in his supervision of Foster (D), but that this negligence had not harmed Doull. Ps appealed. We transferred the case from the Appeals Court to this court on our own motion.