My program has a long reputation for top-ranked AP training, but in the last ten years has made a name in CP training as well. PGY1-2 was spent in straight AP. PGY3-4 was for CP and six months of "big P" electives in which any aspect of pathology was supported.
With CP strictly segregated, it provided a unique opportunity to truly indulge in CP without having to cover AP calls or fill-in AP duties. The segregation also allowed CP to feel like it was given equal weight to AP.
CP was organized into two month introduction blocks of heme, micro, chemistry, and transfusion. Then you would do another one month return visit to heme, micro, chemistry, and transfusion. Then you would do coagulation, molecular pathology, cytogenetics, biochemical genetics, VA, and pediatric lab medicine.
Teaching in CP was organized but flexible. There were daily didactics following a set curriculum. There were individual rotation-dependent didactics. There was some watching techs do their work on the bench. There were some meetings. The main goal however, was to place the resident into the role of the section medical director. Depending on how each resident directed their learning, you could have a lot of reading time or little reading time. Residents gave frequent formal presentations. On almost every rotation, I arrived by 8:30am and left by 5pm. But heme called for longer hours. Sometimes residents would stay until 10pm when the service got busy. I will pre-emptively state that long hours do not make a program "malignant". It's doing things that are a waste of time that is "malignant". If your day packed with learning and meaningful work, then you should be thankful.
CP is not easy to teach. Lab management is not easy to teach. I don't know who does it the best. Although I do not have direct experience, I have heard that the best CP programs are Univ. Washington, ARUP, and Mass General. But I would add my program close behind them, but even though there were concerted efforts to teach lab management, most residents were pretty turned off by it.
How about boards preparation? I am very thankful for my particular training program, because I think we sail through the CP boards. I'm not sure I missed a single transfusion question (although I will never find out since they don't reveal your breakdown). The lab management questions were hard to narrow down the best answer. I always thought to myself, "I don't know what the REAL answer is, but I know how Dr. ___ would handle it at my institution." And I was amazed that some of the questions I knew only because of a random experience I had in the lab where I learned a nuance that I never encountered in a text book. This is why it pays to pay attention during CP, and to go to an institution with a large CP program.
My program has a large transfusion service and operates its own blood collection and manufacturing operation. My program also has a large in-house HLA laboratory. We have an enormous molecular pathology, cytogenetics, and biochemical genetics operation. Unless your program performs CF testing by Luminex or does fragile X testing by southern blot (for instance), you might miss the nuanced question about those methods. Reading from a text book only goes so far.
One final personal thought. CP was one of the best experience of residency. Part of my bias is that I was an excellent medical student both pre-clinically and clinically. But in my first two years of AP, I was humbled and frustrated by its fragmented, non-sensical, tribal, subjective nature. When I first learned AP I felt pretty mediocre and felt surpassed by colleagues who were really smart, but who had long purged their knowledge of the coagulation cascade, the B12 cycle, heme synthesis, or the anatomic branches of the celiac trunk. But when I got to CP, I shined and felt awesome again.
The CP experience was fantastic and only surpassed by my general surgical pathology fellowship (but that's a story for another day).