Epidemiological Studies: A Beginners guide 

Summary notes of study types: 1. 1:09 Ecological Study: comparing health of groups in different places or at different times 2. 1:52 Case Series: describe characteristics (demographics, clinical presentation, prognosis, unusual observations) of a group who has same disease or exposure. 3. 2:19 Cross-Sectional Study: snap shot at a given time on health in a group (e.g. health surveys) (also called prevalence studies) 4. 3:16 Case-Control Study: establish chance of exposure to a risk factor in cases (e.g. patients) vs controls (healthy individuals) over time (odds-ratio calculation) 5. 4:54 Cohort Study: follow group over time and check risk factors along the way (relative risk calculation) 6. 6:52 Interventional Study: double/triple-blinded randomized-control trials (e.g. test effects of a new drug) Overview studies of multiple studies: 8:52 Systematic review 9:08 Meta-analysis Study types 1,2,3 are ‘snapshots’ at a single point in time, while Study types 4,5,6 are ‘longitudinal’, meaning over a longer time period. Study type 4 is mostly retrospective (looking at the past), while Study type 5 and 6 are prospective (looking at the future). Study type 4,5,6 can determine or describe probability of causality, which is not possible in Study types 1,2,3. Study types 1-5 are ‘observational’, while Study type 6 is ‘interventional’. Watch the full video for examples and listing of advantages and disadvantages!

Exam notes: 1. Process of epidemiological studies: Study question --> select a study type --> collect and analyse data --> interpret result --> report finding. Finally, it should be done in an ethical way 2. Ecological study: applies to groups and not individuals. - Useful for comparing health across multiple places (e.g., measles rate across Australia and New Zealand), or comparing two time periods in a single place. - Generating questions that can lend themselves to future investigation and studies. 3. Case series: - Characteristics of a group of people with same disease or same exposure. The aim is to understand demographics, presentation, prognosis or other characteristics of people who have a particular disease. 4. Cross sectional study: -It takes a selected population and measure health information at a given point of time, giving a snapshot of health. E.g., using surveys. They are also called prevalence study. Selected population should be representative of the total population. Advantages: - Relatively inexpensive - Assessing exposure/outcomes - Assess health needs Disadvantages: - Cannot be used to measure causality 5. Case control: - Starts with cases, people with diseases. Uses a control group, similar people but no disease. Both groups are asked about their exposure to certain risk factors, and then odds ratio is calculated as given below: OR = odds of being exposed - case/odds of being exposed - control If OR>1, risk factor is associated with the disease If OR=1, risk factor is not associated with the disease If OR1, increased risk RR=1, same risk RR

This video has taught me more in 10 minutes that my epi class taught me in 5 weeks.

The way I'm going to remember this voice while writing my exams!!!!!!..Thank you so much really helpful..Epidemiology exams you can come now for all I care I'm going to Ace you....

This is the best video I have watched to understand biostats/different studies in a short time, a tremendous thank you to the makers!

Finally, I know the difference between case control and cohort study. Thanks a lot.

Thank you professor Liwen Zeng at the UofA for providing this link. Executed with me in mind. Intuitive, succinct, and informative.

I love how you chose to animate/play out your voice over with the graphics! I saw this video in class when I was initially learning the various studies and it helped me a lot!

Superb.... :-) So simple and nicely presented. As a student, we need these topics to be presented as interesting as this video was. Thank you and keep uploading more of these types of videoes....

Thank you so much! Although I'm German and not that good in English, I was able to understand the topic much better than with the help of regular German literature on epidemiology.

I’m a current MPH student and this is a very succinct presentation. 😊

Thank you for investing your time to produce and upload this incredibly useful video!

You don’t know how this video ease me , it’s like a cold water in a hottest day , thank you 🌺🌺

I have been watching your videos for the last hour and they are brilliant. Thank you! I've been studying my lecture notes, and reading my text book but I find your quick tutes tie it all together! They are so good. Thank you again.

I have never understood medical statistics better before. Thanks a lot for your video😊

You really made me have interest in public health dentistry . Please do make more vidoes on it . Make on biostatisticis and others . Thankyou for helping learner’s like me . Great job 🙏🏻

I absolutely love this video. I'm currently in my M.Sc Public Health. I had to learn this so many times but it was so helpful as a refresher. Maybe a little fast :) Please keep up the good work

Better than my epi class for years 😂 thank you.

Thank you so much! It helped me study for my Disease Detectives Science Olympiad Test. Very helpful information.

enjoyable ,clear and time efficient ...waiting for more such great work

Prefect job We need more videos like that In public health

Thank you a lot Dr. This vieo will help me at my exam.

That was very very very helpful, thank you it helped me a lot to understand the material and get high mark in my exam.

woowww!!! this video is amazing!!! i was in the university, listening to my instructor for about 1hour and 20min and I did not understand anything, but now I get everything!!! thank you so much

Best video ever on this topic, thanks a bunch doc

Great video with wealth of information, Thank you.

Excellent work has been done by the video maker in this video and really clearly the important epidemiological designs has been addressed by the vocal person. Thank you so much sir for this hard work that you are doing for us. Waiting for more videos like this.

I agree. with Xender. Upload more examples and information. Of all the videos that are available on the Internet, this is one of the most helpful. I have been studying on my own for a Board Certification exam which includes epidemiological studies. This overview has been helpful in shaping my perspective of the topic.

Pretty good and clear. Relax background music for focus on the content.

Amazing video. Honestly. So clear and concise. Thank you!

Got more information within 10 minutes. Thank you sir ☺️ 👍

An easy way for my students to understand the different Epid. strategies which supported my teaching material.

Very informative , simple and helpful

thank you! it’s 2am and i’m still studying and you helped me by putting all that information into one video which was kind of fun to watch! could you do more videos of topics like salutogenisis and the process of a study?

Thank you for this teaching. Nice presentation.

these videos are like torchbearer for epidemiology students. please come up with more more videos

I learn from you which I could not from my teachers for the three months. Thank you so much for your hard work and good explanation!

Excellent video. Today, I read 3 chapter based on that information. I finally assimilated the info because of the help of this video.

Thanks very much. I now have a better understanding of the mentioned studies.

Curti muito seu vídeo. Obrigado pelo trabalho em que você trabalha nesses vídeos!! Eu sou apaixonado por temas relacionados à saúde. Efetivamente, eu trabalho com telemedicina, oferecendo atendimento para todo o Brasil! Mantenha o ótimo trabalho!.

This helped me study for science olympiad! Thank you so much!!!

Excellent presentation. Helped a lot for a quick review before exam.

Thank you very much for making this wonderful video, I didn't understand it with my teacher in university and my exams on the horizon after 2 week I saw feeling lost until I saw this video. Many thanks for this video.

Thank you very much, greeting from Mexico.

THANK YOU!!!!!! Excellent video!!!!! Now I feel I can crush step 3

Beautiful summary, amazing! thank you

Thanke you sooo much 💖💖🌸 Excellent explanation

Thank you so much for sharing.

Thank u soo much for this...i always thought public health dentistry is boring n i can never learn it....but nw i think i can prepare well for final year ....

This was so helpful. I just started following. I'm a 1st year MPH student and Epi has been very difficult but the way you broke everything down was GREAT! Thank you. Please share any other resources you think would be of help to me.

So helpful for my exams in nutrition! Thanks!

your work is great. easy to follow and understand.

Satisfactory lecture with easy apprise way......

Awesome lecture. Thank you.

Thank you sir u made my life easy..

Very well done video. Thanks.

These 10 minutes taught me more than i studied for a whole year

This will literally help me in making of my research. My research is coronaviruses and this video help me alot.

Great one, thanks a lot!

This was excellent !! Thank you so much

thanks... i'm having serious trouble remembering these, but this video has helped!

Thank you so much from Saudi Arabia Very helpful , i loved the simple language ..

Simple and clear 👍🏼 thank youu!!!

Thank you so much for this video.... it's too easy to understand in 10minutes .... while the class takes 2 days.

thank you for your great effort, from Egypt

Amazingly explained 🤗

Excellent video ~ thanks!

Great explanation..Thanks a lot! It really helped me for my diplome thesis....

no words just thank you!!!

Really helpful.. Thanks a lot🙏Keep bringing such informative videos..

i am epidemiology lecturer but ur presentation is amazing

Very good!

thank you...I can understand..upload more videos...

Thanks for making this topic accessibile!

Thanks :) Great explanation !

very informative....thank you sir

great explanation. pls upload more videos.

Very helpful video ! Thank you

short but informative. thank you

An amazing video

Best video i have ever seen

so helpful in my public health studies

This Video is really helpfull. thank you so much

Thanks. do more lectures.

Amazing video!

your amazing. thank you.

Thank you! very helpful!

पहला सुख निरोगी काया दूजा सुख हो घर में माया,great info

I feel a need on more explaintion on cross-sectional study. There must be some sort of comparison ( between groups in this case) in order to explain the influence of a factor.

Very educating.

Very informative 👍🏻👍🏻👍🏻

Hi! Could you please explain the retrospective cohort study?

this cleared so many things out. thank you so much

Great work

Thanks for uploading.a slight confusion what's difference bw ecological and cross sectional study

Very informative , simple and helpful:)

Very nice overview :)

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Best explanation ever ty!

Sooooo nice.. Thank you