Here are my replies - to which others may add if they have additional information or ideas
1. On the smoking question, the term "core component" implies that implementing them is essential for successful outcomes. Sometimes elements of our interventions that we think are essential turn out to be not so essential as we thought when put into practice. So, I am wondering whether you know the extent to which the 3 core components you describe can be implemented independently of each other, and whether the effect of implementing them together is additive or synergistic in terms of outcomes. If you know for certain that your smoking program cannot work if all 3 core components working together, then it does not make sense to enroll sites that can't do the whole package. If you think that implementing just one or two of the 3 components could make a difference and that in reality most participants can't really do all 3 components easily, then allowing sites to eliminate or alter certain components could end up providing you with results that will be very useful to the intended end users of your program.
2. On the questions about FOBT and FIT test positivity, the rate can depend on a number of factors, including the brand or type of kit you use and whether the population has been screened before. In a previously unscreened population, the test positivity should be a little higher -- for example up to 10% in some studies -- since you will initially pick up more people with untreated cancers and polyps. Over time, the rate could decline to under 5%, as the initial group of positives gets follow-up colonoscopy, including removal of polyps and early cancers. The guaiac FOBT tests tend to have a higher false positive rate that then newer and more accurate FIT tests. FIT stands for "fecal immunochemical test" and it is specific for human blood, and is not influenced by diet. The kit manufacturers usually publish an expected positivity rate, and if you are running a big program where you need to project colonoscopy demand and match it with capacity before providing the kits on a large scale, you can start by just using the kits on a few hundred patients to get an idea of the likely positivity rate for your patient population and practices. I am assuming the reason you asked this question is because the more positive FOBT and FIT tests you have, the more colonoscopy followup you will need to do.
3. On return rates for kits dispensed: Return rates for the cards can vary from about 30% to 70%. In our studies, we have typically had a return rate of 40-50% when there is no follow-up, and this can go as high as 70% or even sometimes more when you provide follow-up telephone calls, typically first between 2 and 3 weeks and again at around 4 to 6 weeks if at first you get no response. Reminder postcards can also help, but they do not seem to be quite as effective as personal telephone calls from someone who is prepared to send them a new kit if they lost it, or to just encourage them to complete the kits. Return rates are also higher when the kits are provided with a postage paid envelope -- asking patients to bring them back in person or put their own postage on the kits is an impediment to returning them. These return rates are similar to return rates when they are handed out by a primary care clinician. I think they will generally be higher when they are provided in a setting that the patient knows well and trusts. Fortunately, the kits only cost the clinic $1-2 each to dispense (including a postage paid envelope) -- which you can usually recover by billing just for the kits that come in. If anyone wants to talk more about the issue of how to make your programs "cost neutral", I'd be glad to share more thoughts and ideas. Another point to remember is that FLU-FIT/FOBT programs are really meant to complement other types of screening outreach -- often people need to be asked in several ways before they complete recommended screening, and the FLU-FOBT/FIT programs are meant to provide people with an "extra" opportunity to get screened or get convinced of the improtance of colorectal cancer screening. Everyone knows about the importance of flu shots, and by adding FOBT/FIT you can help to create a new community norm and expectation over time.
Thanks for these excellent questions!