What is public health?

today we're going to explore the question what is public health I get asked this question about once a week what is public health what do you mean by public health now if you look up a definition of public health if you look it up online or look it up in a dictionary you're going to get something that's verbose it's going to be wordy it's going to be flowery what I'm going to do is a little different I'm going to say look let's have a very simple definition of public health and then as a separate question let's ask what do public health professionals do so really what we're going to have is a simple definition and then some complimentary jibber-jabber so here's my definition of public health public health is a discipline that addresses health at a population level no more no less that's the definition now we can add on some complimentary jibber-jabber to try and understand that a little better so for example we might want to talk about the fact that public health is different from clinical medicine and other paramedical disciplines like physiotherapy and occupational therapy which deal with patients at an individual level public health really looks at groups of people in those groups include sick and well people and those groups are delineated at any level that you want it could be a community it could be a country and of course it could be global health now let's take a closer look at the second question what do public health professionals do well public health professionals try to do two things really the first is to understand and the second is to act now let's look at each of these components separately and then we'll look at how they work together when I say that public health works to understand I really mean that we gather information and evidence that will inform how it is that we intervene and act to understand population health we do two things really we do surveillance and we do research we're trying to learn more about what we call exposure so exposure could be risk factors what could be interventions and we're trying to understand outcomes disability and disease and with respect to all of these factors we want to understand their distribution and their magnitude so magnitude is kind of self-explanatory it's how big how much and with respect to distribution we mean distribution geographically so physically where are these exposures and outcomes and of course we mean distribution sociologically across for example different socio-economic groups or cultures etc so we're doing the surveillance and this research to understand the distribution and the magnitude of exposures and outcomes so that we can do two things firstly we want to understand the causal relationship between exposures and outcomes and secondly we want to plan interventions to improve public health and of course these two things are connected so the better we understand the causal relationship between exposures and outcomes the better we can plan interventions that we know will work and will have an impact on public health so we've talked about the first area where public health professionals work and we've shown how this all leads to a point where we've got a better understanding of how it is that we can intervene and plan programs that have an impact on public health and so this of course leads us to the second area that public health professionals work which is to act in other words we want to act on that understanding right so we intervene really in two ways we want to keep healthy people as healthy as possible and we want to ensure that people that are unwell have access to care and treatment so let's look at the first one first what do we do to prevent disease and disability well we do two things firstly we promote behavior change and secondly we reduce exposure to risk and of course as you can imagine there's a lot of overlap between those two so with respect to promoting behavior change there's really two things that we try to do we want to promote behavior firstly that we know will have a positive impact on health like improve diet exercise etc and of course we want to deter behavior that we know will have a deleterious effect on public health like smoking then with respect to actions that we take to reduce exposure to risk we do this by addressing two kinds of risk firstly there's the physical and environmental risk factors that people are exposed to things like radiation water contaminants and safe medicines and secondly there's what we call the social determinants of health things like human rights violation gender discrimination etc so now we've talked about what we do to prevent disease and disability in otherwise healthy people now let's talk about what we need to do to ensure that care and treatment is available for people who are unwell so as you can imagine I'm going to tell you that there's two things that we do the first thing that we're going to do is we're going to use best evidence we're going to lean on that understanding that I referred to in the first half of this talk and we're going to use that to advocate for policy change that ensures equitable access to safe and effective treatment in other words we want to make sure that all people have access to health services and the second thing we need to do and of course it's related to the first is we need to ensure that the health systems are in place to provide care and treatment for people that need it now health systems can be thought of as two things the first is capability and the second is capacity capability is what you're able to do what you're capable of doing and this is really a function of things like health service planning governance leadership information management etc and then there's the other side of health systems is what we call capacity how much you're able to do and this tends to be a function of finance products and human resources in other words the more money the more products and the more people you throw into the health system the more capacity the health system has in other words more people will get treated so that's really public health in a nutshell like I said at the beginning the definition of public health is that it's a discipline that addresses health at a population level what it is that public health professionals do well that's a slightly longer conversation what I've talked about here certainly not comprehensive I mean there's more to public health in what I've mentioned but this is perhaps a good schematic that you can use to place the studying or the work that you're doing in the context of a broader set of activities thank you for listening I hope you found this useful you


  1. Dear Greg, I absolutely loved this video. I worked Public Health in the Air Force for 7 years and you perfectly summed up an explanation I've been looking for. Is there anyway you have access to a printed version of this videos diagram?

  2. Want to study public health in masters level..
    At the moment I’m a student studying Bsc. Business Administration ..

  3. i 'am leaner student public health
    so don't know more and more information about public health
    so i need to health prof plz adn plz

  4. Hi dr. Greg, thank you for the video, really informative and easy to understand. I'm getting an MPH right now. I want to ask something. Nowadays it seems the professionals from Epidemiology and Public Health are saying the same definition and objective between them, that is like what you are saying, to understand and to act. I am told that an epidemiologist also look for solution to a problem and a public health officer also research and survey for diseases. I want to ask what exactly the real difference between Epidemiology and Public Health at this time? Thanks.

  5. Join the #CME & #CPD Accredited 9th Edition of International Conference on #PreventiveMedicine & #PublicHealth during July 16-17, 2018, at #London, UK. Visit: https://preventivemedicine.euroscicon.com/registration

  6. I usually get stuck when people ask me what do i do as a public health doctor…even my colleagues from the clinical field think that i do administration work..😣😣😣. Thank you very much for this short and precise definition of PH

  7. Thank you very much for this video, i am now studying public health at cuttington university in liberia.

  8. I really confused bt u made me understand can I have a words with you..Please because I literally very confuse for my career option still alot of questions are also uncleared till now.its request

  9. Hi , I’m from Saudi Arabia, in my first year in college of public Health. My question is after I graduate and get a job what i do on my work field?

  10. Thank you so much for this Topic
    Iam from sudan
    Iam public health student
    I have some quations
    Now I study in this year
    introduction to public health
    Medical entomology
    Vital stastistic
    Drawing and building concentraction
    Iam freshman in this college
    tell me some books to help me to understan the concept of this college
    I need profission in this college insha allah

  11. Excellent video thank you so much for the explanation of public health, am bachelor holder of public health.

  12. Thank you for this video!! It´s a good summary to explain the field of PH.
    BUT unfortunalty it`s not right if you say "More money I put in the Health Care System more capacity the HCS has" (5:03)
    Look at the Outcomes of the HCS of the US – the most expensive in the world. Despite of the money they put in they have not more capacity or better outcomes in morbidity or mortality. Social Inequality is the magic word i missed in your video. The gap between economic interests and public interests influence the intentions of PH.

  13. thank you sir for this information
    but I have one question
    I,m public health student
    when can I found the
    public health books
    place can you give me
    name of the some book
    in public health in online
    think you so much

  14. I have master degree in public health from Egyptian University . can u help me to get PhD degree in public health from any American University???

  15. Is global health and public health more or less the same?
    I am planning to do a masters in global health. Would you recommend this path?

  16. I'm an engineer who is interested in public health. I had a serious burn injury that allowed me to have close contact with clinicians. I'm interested in epidemiology and policy. Will I be able to transition well without that clinical background?

  17. Thank sir for the knowledge on public health…. I'm Mcdoulf Musah Jr, I will like to take public health as my career, but do not know where to start form sir…. Can you please give me some advice…. Thanks

  18. Hello,please I am interested in taking a masters in public health but I had a degree in Linguistics. Will that be possible?

  19. Great video. What accent is this? I'm not saying it's bad – it ISN'T – but I would like to know where Mr. Martin is from.

  20. I'm a Social Work student. I've just began my studies and we're looking at the differences between the different concentrations within the Collaborative Human Health Services field. Just wanted to say, "thank you." This is by far, the best explanation of Public Health I've seen.

  21. This really really helped me! I was particularly drawn to your diagrams- they were clear, aesthetic and easy to understand. Well done.

  22. Hi Greg! I really enjoy your videos! I'm thinking of pursuing an MPH but many programs seems to want experience in the field which I lack at the moment. I'll be graduating next year, do you think it would be a good idea to get some experience first before applying for the programs or is there a way to get accepted without the experience?

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