Use of the cannabis and securing of a university title

Yesterday, the Delegation of the Government for the National Plan on Drugs presented II report on the cannabis. Apparently, during the presentation, if we have to pay attention to what they have gathered the newspapers, I protect Sánchez, expert in addictions and one of the writers of the report affirmed (or this way it was understood by the journalists who gathered his affirmations, which everything can be) that, according to international studies, only 2 % of those who have consumed cannabis in his life obtains a university title, opposite to 30 % (or 38 %, according to the source) of those who have never consumed it.
I say already to them that I do not know if it is a question of an affirmation of the expert or of the shift journalist understanding, but the difference is so showy that outsider sounds, especially in view of the panorama of consumption of cannabis in any faculties.
Let's see what the original source says, II report on the cannabis:

In a study of pursuit of 1265 children for 25 years realized in New Zealand, it was demonstrated that there was an association as per statistics significant between the consumption of Cannabis of way dose - clerk and a major risk of abandonment of the studies, of defeat in the access to the university and of finishing the university studies prematurely (Fergusson et to., 2008). In this study, 1,9 % of the students who achieved to obtain a university title had a high consumption of Cannabis (more than 400 times before 21 years) opposite to 35,9 % of the students who obtained a university title and had never consumed Cannabis.

It is clear: no? No, skylight that not. If we pay attention to the writing we will conclude that 1,9 % of those who obtain university title has a high cannabis consumption, while 35,9 % of these alumni has never consumed it. But this is something different from what the expert said.
Let's see, then, the original study of the one that the information obtains, that of Fergusson et to. (2008), which is: Fergusson, David M. and Joseph M. Boden. 2008. "Cannabis uses and later life outcomes", Addiction, 103, 6: 969-976. They can consult the summary here, but the article is not free free. The information to which there refers the report on that we comment comes from the picture 1 of the article. They are gathered in the following picture.

Now yes it is a little clearer. What says the study is that, between the born in 1977 in the Christchurch locality, New Zealand, the biggest frequency of use of cannabis between 14-21 years, measured across surveys and turned into the number of times that consumed it in these 7 years, collaborates clearly with a minor securing of a university title at the age of 25 years. Those who less obtain it are those that more cannabis has consumed (400 times or more in the mentioned ages), since only their 1,9 % obtains it. Those who have more success, with 35,9 % of qualifications, are those who have never consumed cannabis. That there are two groups to which the informations seem to refer. It is obvious that that of 1,95 % all the cannabis consumers do not form, but only the very frequent ones.
In fact, for the set of consumers of cannabis, the qualifications valuation is 21,5 %.
The true thing is that yes an effect seems to be observed between the consumption of cannabis and the university success. In fact, even controlling the influence of other possible factors that can influence the academic achievement (1), not cannabis consumers had a probability of completing university studies four times superior to that of the very frequent consumers, although not 18 times Superior as he suggests the picture that we have seen.
Anyway, I hope that, more or less, the information should remain this way clear. After all, they are told itself by a university student who has not consumed cannabis in his life :-)
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(1). Age of the mother, educational level of the mother, familiar socioeconomic status when there was born the subject, standard of familiar life (age 0), exhibition to sexual or physical abuses during the childhood, familiar adversity, use of illicit drugs for someone of parents, crime of someone of the parents, alcoholism of some of the parents, problems of conduct (7-13 years), problems of attention (7-9 years), I consume 10 of alcohol (15-21 years), association with problematic pairs (15-21 years), you notice in the school (11-13 years), I use of other illegal drugs, between others.