We need to distinguish among kenyan runners using doping.
There are 2 different categories :
a) athletes of international level
b) athletes of amateur level (amateur for Kenya, of course).
In the first category we can put the most part of athletes living and training in some camp, managed by a Company. Normally, these camps have one or more coaches, and a physio, working with the athletes full time.
I don't say some coach or manager goes to administer some doping, but directly from the managements there is the advice to use supplements of various composition, creating in the mind of the athletes the idea that, without this type of support, their training can't reach the same level of volume and intensity.
With this type of mentality, many athletes join to the legal supplements, given by their management, some other substance they decide to use (many times after talking with other athletes sharing their experience), without asking anything to the management, insteadb following the medical plan suggested by some doctor (who take a percentage of the winning prizes of the athletes).
We can say the managements or the coaches are directly responsible of the athletes' doping ; however, they are the INDIRECT responsible for building that dangerous mentality.
The athletes, also if living and training in some official camp, are not prisoners, and it's not possible to control them for 24 hours every day.
The real question is : which type of specific education, not only against doping, but above all the values of sport (loyalty, solidarity, fair play, improvement of self confidence, support for who is less strong or less lucky, etc...) the coaches of the camps, and the managements, try to give their athletes ? Because I know several cases of managers and coaches who, having doubts about some of their athletes, simply don't do anything, waiting to see the evolution of the situation.
Different is the case of athletes of amateur level. Amateur not for the level of their performance, but for the situation around them.
To this group two typology of athletes belong : athletes with great talent and potentiality, training alone in very soft way, before finding some good coach who put them in some management (for example, the case of Brian Komen, 25 years, never running till last year, who won one of the AK meeting in 3'35" supported by James Kwalia, who was a my athlete winning bronze medal in 5000m in Berlin 2009, before going in the management of Hussein Makkè, and who won his first competition in Europe with 3'33", but of course doesn't have the requested number of OOC tests, so can't run Trials). Because of their talent, these athletes in short time are recruited by some good management, and automatically move inside the group of athletes of international level.
The second typology (regarding road runners because are the only Kenyans, if not of high level, who can find some competition) includes athletes without coach, without manager and without organization, who join some organized group for training without any specific program, and are helped by some other old athlete of the same village for going to run abroad, mainly in Asia. These athletes don't have any advisor, and represent a percentage of 90-95% among kenyan runners tested positive.
In this case, we see the name of substances that nobody knows, and that don't give precise advantages for the performances : everything is casual, these athletes strongly believe that drugs can change dramatically their level, but take illegal substance without any plan, may be adviced by some doctor taking advantage from their ignorance.