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Hi, sorry no video yet on sample size calculations and power. It’s a complex topic and depends on type of study and what other information there is about the population.

See czcams.com/video/-pwQJYjWWMc/video.htmlsi=i_mqCIuzuJZQ_K5O, you can use Cochran’s formula with variability of factor of interest in population being 50%, the largest variability, with 95% confidence interval (z= 1.96) with precision (p value) of 0.05, worth watching all of it but this discussion is at 07:23 onwards. PS: likely size of your population is important what’s the total pool of people from which sample is taken. Where population isn’t the large i.e. the whole population e.g. population with some kind of chronic health problem which may be small. In this case see the other formulas in this video.

Thanks, yes I used to teach it but it’s a counterfactual model in that we used to develop policy based on assuming that people are highly intelligent people who understand all the consequences of a policy and will not make decisions based on political and personal world views that they believe strongly in even when the evidence is against them. Over time it’s clear that we are not rational actors but influenced by a range of individual, community and societal norms and perspectives including religious beliefs and short term factors e.g. poor people are lazy, I am successful because of me and both are nothing to do with the society I live and the family I was born into through no choice of my own. Hence the lecture focuses on models like Kingdon that are more useful in understanding how policy actually happens and how people actually act - both rational and emotional - rather than what we hope people will act like.

Yes, you are correct. At the beginning (before exposure) denominator is all the people at risk of heart disease but not those with heart disease already. I was explaining from the end (after exposure has occurred) hence my phrasing, thanks for the feedback, helpful for when I update this video in the future.

I really appreciate you taking the time to reply. Thank you for explaining it. I’m just starting out in epidemiology and it’s all a bit confusing.

Asking questions is the first step no matter how silly we think the question is. Thanks for asking as it also helps me reflect on how I teach epidemiology, I’m still and always learning!

Hi, No as I don’t want people copying directly as then plagiarism will become an issue for students. It is straightforward to pause and use your understanding to summarise using your own words. That way the material remains useful for students for years to come.

Hi, before you can analyse a policy you need to be able to understand and describe it. See, czcams.com/video/xYu4LqZzkeA/video.htmlsi=DcHj1CXrrreyYi4r once you can summarise the key elements of it you can then start finding materials to analyse things like content of the policy, the wider context in which it was developed, why are/were a specific set of origanisations/individuals involved, why was the process of policy making the way it was (this is hard as often not much public info on this). The analysis using the policy triangle means looking for articles, reports and books that critique, analyse, review the specific policy you are analysing yourself. From there you get your own ideas. You can also find research evidence of whether the specific individual parts are effective. Google search - critique analysis review of, history or trends in country X policy e.g critique of UK housing policy, analysis of England obesity policy, history of US HIV policy and so on.

Hi, Thanks for the feedback and question. Can you clarify what you mean by doing a health policy study? And what area of policy are you doing the study on?

Thank you for your return. I want to work on lean management in health institutions. I have read a study before and I will give the information of the study below. I would like to study lean management with the Scoping systematic review method used in this study. Is there a video on your channel about this method? I think it will help the work I will do. (Qudsiah, S., Kang, C. Y., Fatimah, A. F., Zamzaireen, Z. A., Natalia, C. I., Mohamad Fadli, K., ... & Juni, M. H. (2017). Methodological approaches of health policy analysis in developing countries. International Journal of Public Health and Clinical Sciences, 4(2), 19-36.)

Sorry for not understanding, you have 3 things in your answer, that need more clarification. Policy analysis is either analysing existing policies on for example alcohol, drug, smoking, nutrition, obesity, housing, and so on. It can also mean the process of developing a new policy agenda setting/problem identification, identifying policy options to solve the problem, and so on. I don't think there are any policies on lean management in healthcare institutions. So, I think you want to do a literature review not a policy analysis. A literature review on lean management in health institutions needs to have a clear question. Are you looking at, for example, how widespread is the use of lean management in healthcare institutions e.g. hospital; or how effective is lean management in healthcare institutions in delivery high quality services. Are you looking to do something like this: Mahmoud, Z., Angelé-Halgand, N., Churruca, K. et al. The impact of lean management on frontline healthcare professionals: a scoping review of the literature. BMC Health Serv Res 21, 383 (2021). doi.org/10.1186/s12913-021-06344-0 bmchealthservres.biomedcentral.com/articles/10.1186/s12913-021-06344-0

Hi, nice spot, technically yes but in practice no. This is because the whole study period is seen as the unit of time (the time period for the risk). Otherwise we would have lots of different risk estimates depending on what years we selected. In the example, if we just looked at Year 1 the risk is 1/7, in Year 2 1/7, and in Year 1 + 2 it is 2/7. This is the reason why the rate estimate, in person-years give the more accurate estimate of the probability (chance) of dying because it takes into account, the number of people who died, the number of people who were exposed at the beginning, and the years of exposure. While risk only includes the number of people who died, and the number of people who were exposed at the beginning. This is why risk is easier to understand and use, but less accurate than rate, which is more accurate but harder to understand because person-years is not a idea we can intuitively understand and make sense of. It's not a concept we can link to everyday life.

@@ScienceandArtofPublicHealth Thank you very much for your in-depth reply! That makes a lot of sense!

Thank you appreciate you taking the time to make a comment. What in particular did you like?

Thank you very much, if you have time, two questions, what 1 thing did you really like about it, and when you say more, what more, there are video lectures on the other 3 key types of study designs, randomised controlled trials, and ecological and cross-sectional studies.

Hi, I don’t give these out, as if you need to, you can easily create your own or it’s better to write your own notes using your own understanding of the slides.

Hi Stuart, You start by looking looking at the 'Contents' as that's the easiest to do, you identify the aim, objectives, key principles and key interventions/actions set out in the policy. You then analyse/evaluate these in terms of how they relate to public health principles and values. For example is/are the aim/objectives focused on individual level behaviour change (i.e. That individuals are responsible for their own health) or does it (also) focus on structural societal factors like poverty, discrimination, lack of educational and economic opportunities, poor access to services and so on. This comes from close reading of the policy itself. Then you move on to 'Context', what were the social, cultural, economic and environmental factors that created the need for the policy (or revising/updating) the policy. This comes from finding critiques and analyses of the policy and searching for historical overviews of the policy e.g. critique/analysis/evaluation of X policy in Y country, using those three words separately and together. These are often journal articles and sometimes they are reports. You also need to a analyse how and why the content of the policy has changed over the last 20 years. This will help to identify the contextual factors. Then you look at 'Actors', which ar the key groups that have a interest/stake in the policy. In a previous video lecture, I identify 7 general types - international agencies e.g. WHO, national and local government, business, NGOs, research organisations e.g. universities, institutes, think tanks., and communities/general public. you need to work out what the specific ones are for your policy. Not all actors are directly involved in developing the policy but often in some way they have influenced it. Sometimes they are mentioned either in the final policy or in consultation documents relating to a draft of the policy before it was finalised. In UK, green papers are consultative documents and white papers are the final policy the government sends to parliament for members of Parliament to vote one. Last an hardest is the 'Process'. It is often difficult to find out about the process directly, Often it is through searching for researchers who have done the research and written a report or more likely a journal article discussing the policy process, e.g. policy process for development of X policy in Y country.

Thank you so much for this fast and so useful answer, I’m truly grateful!

I'm glad, its an excellent topic to develop a hypothetical proposal for. Well Done!

My apologies for not replying sooner, thank you for the question, its a difficult question, hence my delay. One simple policy framework by (See, www.healthknowledge.org.uk/public-health-textbook/medical-sociology-policy-economics/4c-equality-equity-policy/problems-policy-implementation) argues that there are 4 key elements, content, context (social, cultural, economic, etc.), process (of policy-making) and actors (people and organisations involved in policy making). If you are talking about how to extract key aspects of a policy, then use the Table of Contents to work out the Aim/Vision, and key objectives of the policy and then, if discussed, key principles, and then what interventions/actions/activities that are recommended set out in the policy that other stakeholders at national, regional and local levels will implement.

also please can i get your mail for further public questions

Best is to use the comments as I don’t get much chance to look at emails (really, even for my own students) and this way other people can also learn from your questions.

Hi, thank you for the comment, really appreciated. There are so many good books, every book provides a different way or perspective (lens) into public health, but if I have to choose 4 books then I would recommend 2 books at BSc level, the simplest book we use is: Jane Wills, 2022 Foundations for Health Promotion, amzn.eu/d/6H5WmjU (used to be Naidoo and Wills in the older versions or second hand), the one that then builds on that one is Green et al (2019) Health Promotion: Planning & Strategies amzn.eu/d/guyAOAF. For postgraduate and Year 3 BSc, Guest et al (2020) Oxford Handbook of Public Health Practice amzn.eu/d/jlBUPrd (nice small one that's handy to take everywhere (aimed at medical professionals but good overview), the other one is a UK-focused one and again a lot packed in as it is what is expected of medical professionals going into to to their postgraduate membership/fellowship applications for the UK Faculty of Public Health. So it covers all the knowledge expected of experience public health professionals working at a high technical proficiency, Lewis et al (2013) Mastering Public Health: A Postgraduate Guide to Examinations and Revalidation amzn.eu/d/1Fd32ct . There are also a lot of books on global public health, the two that are good introductions and give two overlapping perspectives are Sethia and Kumar (2018) Essentials of Global Public Health amzn.eu/d/foW9wKQ and Birn, Pillay and Holtz (2017) Textbook of Global Public Health amzn.eu/d/7THCDF6 .

For epidemiology only. My favourite is Rothman (2013) Epidemiology: an introduction amzn.eu/d/9jJNnMB

Hi, No they’re not. Happy to share on an individual basis as it is simply a PowerPoint presentation.

Thank you for the feedback, appreciated 🙏🏾

Hi, see the Introduction to epidemiology playlist, and czcams.com/video/0mxJjwq1F-Y/video.html

🤗 I’m glad I could help!