kiranb
Forum Newbie
Topics: 2
Posts: 14
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Hi everyone!!!
I just found this site a few days ago..wish I had done so earlier as I am taking the exam next friday!!! You are all so helpful, I wish you all the very best as your test dates approach.
I was lookign through old q's and found this one that someone had posted a couple months back..was just wondering if anyone had any thoughts on the correct answer!
1000 car accidents happened over the last two years in a town with population of 1,000,000. 600 were alcohol related. 400 died because of the accidents of which 50% were alcohol related. what is the one year incidence of EtOH related death?
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| rida
Forum Guru
Topics: 109
Posts: 721
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I know i have seen this question somewhere but i can't remember where, I think the answer is 100, becausew you have 400 that died because of accidents of which 50% are alcohol related meaning 200, but thats over a period of 2 years, so for 1 year, it would be 100 accidents. Hope i am right, if not please correct me!
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"If He takes you to it, He'll take you through it."
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| kiranb
Forum Newbie
Topics: 2
Posts: 14
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sorry rida ..i don't know either! I would also go with 100....but if there was a choice 'not possible to calculate' ..I migth be tempted to choose that one instead as I am not sure that we can just assume that the same numebr of accidents happened in each of the two years! Thanks for your thoughts!!!
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| sudipto1973
Forum Newbie
Topics: 4
Posts: 31
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Incidence rate ia always calculated as new cases per person-years.
In this question person-years = population X years of observation or follow up which will be 1,000,000 X 2 = 2,000,000.
Now, new cases of alcohol related death in that two year time period is 200.
So Incidence rate is = 200/2,000,000 or 1/10000. The full interpretation of this answer will be 1 alcohol related death per 10000 persons per year.
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| docofthebigapple
Forum Senior
Topics: 23
Posts: 182
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The rates are expressed in terms of n/100,000 people per year. In this case the answer comes out to be 10 per 100 000 people per year
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| niti
Forum Guru
Topics: 36
Posts: 499
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Hi
Question is .....
1000 car accidents happened over the last two years in a town with population of 1,000,000. 600 were alcohol related. 400 died because of the accidents of which 50% were alcohol related. what is the one year incidence of EtOH related death?
So,what I got....
Here the Q is about “Alcohol related death “and for that risk group is “ accidents” which is 600….and 400 died bec. of accidents ( 50% = 200 )….so,200 were alcohol related ….
So,Now Incidence of alcohol related death will be
Inidence = 600/200
= 3 ( this is for 2 yrs. )…for one yr…….3/2 = 1.5
Final answer ....One yr. incidence of alcohol related death is 1.5
Please correct me ,If I am wrong.because I think it is a very basic Q...and we should solve this at least ??
roll
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| docofthebigapple
Forum Senior
Topics: 23
Posts: 182
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the question seems easy but it has two stems.
1 600 out of 1000 accidents were alcohol related
2 50% of the 400 deaths were alcohol related.
these are two different statement, one of which has no contributin to the final answer. its designed to confuse.
the question asks only the death rate, not the accident rate attributable to alcohol
Its designed for you to mix up but dont mix them up.
1000000 people-------1000 accidents
600 of these are alcohol related
Now the real stuff starts.........
400 died because of the accidents
" 200 of these die because of alcohol ( 50% )
So there you get the alcohal related deaths
Its 200. divide by 2 to get it in a year = 100
express rate in 100 000.
Answer is 10.
Hope it helps.
 But i also discovered a funny part. In the accidents people who consumed alcohol had lower death rates 200/600=33%
as compared to people who didn't
200/400=50%.
get a point
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| sudipto1973
Forum Newbie
Topics: 4
Posts: 31
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hi guys,
There is no rule which says that rate has to be expressed as n per 100,000. In fact you could be tricked in MLE as I have come across questions where rates were n per 10,000 and in one case rate was n per 20,000. It all depends on what choices you have for your answer. So it is better to keep an open mind and see what the examiners are asking for in the answer. Answer choices usually gives a clue.
bests
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| docofthebigapple
Forum Senior
Topics: 23
Posts: 182
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hi i dont know whether they teach this to the medical students graduating elsewhere, but i studied in punjab in india, where we were taught to express all statistical data in a standardised form, where we would express all such demographic data in numbers per 100000 of the population or that specific group, whatever it was concerned with. Thew book we studied in college was parker and parker.
i think these are international terms and are not restricted to only india or one single college where i studied.
I dont know why sudipto1973 had such an experience in the USMLE where they didn't express rates in the above terms.
I have tried to provide some examples from the web where in different aspects, some statistical data is talked about. the examples below support my assertion.
http://cisat.isciii.es/mmwr/preview/mmwrhtml/mm51...
http://www.developmentgoals.org/mdgun/21.htm
http://www.health.state.pa.us/hpa/stats/techassis...
http://surveillance.cancer.gov/statistics/types/m...
Please give me feedback about other people's experience.
Does USMLE not follow these rules or am i missing something.
THe question asked in the beginning did not provide any answers to select from, so going by my experience, i'd express answers in n/100000 unless the exam question provides me different options.
Thanks.
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| sudipto1973
Forum Newbie
Topics: 4
Posts: 31
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hi docofthebigapple,
that is what I meant. To clear confusion, as a standard convention rates as usually expressed as n per 100,000 but for question purposes you can be tested with different answer options. So answer according to the answer options.
I am an Epidemiology major and I have faced these type of questions on numerous occasions. BEST THING TO KNOW IS: ANSWER ACCORDING TO THE OPTIONS PROVIDED. MORE THAN RATES PER 100,000 YOU WILL BE TESTED ON THE CONCEPT WHICH CAN BE PRESENTED IN SLIGHTLY DIFFERENT WAYS.
Cheers
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