Talk:Number needed to treat

message: Listen up Psarka; I have no doubts you have heard these words before, but I will say them anyways. In this instance at least, you are arrogant and lack both manners and the expertise sufficient to say what you have.
Your nearly 900 word post here is a testament to just how extreme your need to criticize my work is. Instead of spending such an absurd amount of time on explaining why you will revert my edits, did you perhaps think you might instead spend such time on simply making the edits you feel are appropriate? The only thing you have done here is waste your time to justify wasting mine, all while never improving the quality of this article. You seem to have been so incensed by my request not to delete my work without reason that you set out to prove my incompetence just to spite me for making such a bold request.
Your Complaint                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  	Response
"I get the feeling that you are very emotional about your additions, but also that you had a hunch that they will get reverted. What made you think that? Did you saw some weakness in your text when you wrote it?"                                                                                                                                                                                                                                                                                            	Drop your god complex for a moment, would you? Would you like to know why I said what I did? Sure, I'll tell you, even though you deserve nothing of the sort. I would refer you to the specific words I used - "DO NOT REVERT...". I'm afraid I'm going to have to oppose your absolutely asinine theory that I somehow put hours of effort into improving in article all the while somehow retaining the knowledge that I was simply too incompetent to possibly have anything to contribute. In fact, I added such a statement exactly for pedants like you. As I've highlighted, my comment does not say "DON'T YOU DARE EDIT MY REVISION", it says revert for a reason, which is that, unless one has a FACT-BASED issue with my edit, he should focus his efforts on ADDING to the article instead of DELETING my work. Your pathetically patronizing explanation of my statement is a delusion in your thick skull only.
"Or maybe you thought that inevitably some evil guy will show up to destroy your valuable effort? If so, I'm afraid that no matter what I write, you already made up your mind and will curse me to hell.
Well do that, while I will try to do my best explaining my point of view in the politest and most constructive way I can. Here I go."                                                                                                                                                                	Nice save, buddy. Say one pseudo-polite thing to give the appearance that your previous statements weren't thoroughly insulting. Your baseless idea that I would oppose you no matter what you said is utter stupidity. Why, if I was so unable to hear any criticism, would I specify "WITHOUT THOROUGH EXPLANATION OF REASONING"? Do you truly think, not knowing me in the slightest, that my request to not delete my hours of work is an act of absolute arrogance? How exactly would that fit with your previous theory that I am somehow fundamentally confident in my own incompetence?
You can say you're being "polite" all you want. It does not alter how polite your words are. It is laughable that you would call what you decided to do the "most constructive" way you could possibly address your concerns. As I have mentioned previously, you seem to be missing the entire idea of Wikipedia, which is not one of academic sparring, but of cooperative contribution.
First you did not correct many inaccuracies. If you read the old version of that section generously, you will see that all the numbers and notions are accurate. The text is quite poor, I agree, but accurate.                                                                                                                                                                                                                                                                                                 	Here is where I begin to question what article you could have possibly been reading. For someone supposedly so knowledgeable in epidemiology, you have missed many glaring false statements present in the original. Allow me to address your largely invalid, wholly unhelpful points now, in no particular order (if it does not harm your sense of self too severely).
"Your other additions are valuable, but they should find their place in different articles. Why? Take a look at the table at the bottom of the article. NNT is one epidemiological measure out of 25(!). All the discussion in this article should be focused on the NNT itself, and not the broad context of epidemiology."                                                                                                                                                                                    	You know, I am not an idiot. Despite your implication, yes, I am aware that NNT is not the only important term in epidemiology. I have taken epidemiology classes. 
Unlike mine, your negative contribution, in the form of reverting mine, is not valuable. Believe it or not, expounding on one topic will inevitably contain some information on other topics. If it didn't, it would be a dictionary, not an encyclopedia. An article should contain material that is pertinent to the understanding of the article's topic. That requires explaining some things which would otherwise, by your idea of what articles should contain, be scattered broadly over up to 25(!) different articles. Despite the absurdity of your claim, I will address each individual point.
"When I think about the article such as NNT, I imagine a reader that wants to quickly become familiar with the terminology of epidemiology measurements. So they click around and try to understand the differences between the measurements and their usage. My goal is to provide them this understanding as painlessly as I can."                                                                                                                                                                            	Yeah... no. That is not the goal of wikipedia. Clearly, the specific wording of articles should be as simple and digestible as possible, but, beyond this, it would be a disservice to the reader to leave out important aspects of the specific thing they are reading about simply in the name of "painlessness". In every situation, it is better to err on the side of too much detail than too little, as readers are capable of sorting through more information than they wanted, but are not capable of synthesizing from nothing information they do not have.
"That includes not burdening their brain with extraneous information that they could easily find in a dedicated article."                                                                                                                                                                                                                                                                                                                                                                                       	Please explain how you expect readers to find information in a "dedicated article" that is relevant to the information about to be presented to them if you do not provide the reader with any inkling that there is indeed an additional concept to understand before they ought to continue reading? You could certainly argue an internal link to a specific subsection of a different page on the subject could replace this, but you did not edit the text to include that, you instead REVERTED the entire thing.
'Sentence "The treatment may be a drug in the form of a pill or injection, a surgical procedure, or many other possibilities" should find its place in Treatment and control groups or Clinical trial'                                                                                                                                                                                                                                                                                                          	HAVE YOU READ the original article??? It uses EXCLUSIVELY the example of a "pill" being tested in a trial. If I didn't know better, reading this entire section I'd think pills are the only treatment relevant to the NNT measure. So, in fact, the sentence in question is acutely relevant to a proper understanding of the section. If you wanted to say it a different way, perhaps you should have done so instead of REVERTING the entire thing.
Chunk of text "This is typically a type of study <...> but are much more difficult and time-consuming to perform" should find its place in Clinical trial                                                                                                                                                                                                                                                                                                                                                       	I was actually going to edit this bit again as it's not quite correct, but you seem to have missed that and locked in on its relevance. If you'll turn your attention to the section just below you will see the real-life example is a study that involves a group of participants selected, in part, on the basis that they do not have heart disease. In this case, when the primary outcome measure is development of heart disease, the entire design of the study (starting with all sick or all healthy participants) is wildly different, which warrant a short explanation. Unless you disagree with how I did this, in which case you could edit it instead of REVERTING the entire thing.
Chunk of text "The control group may receive a placebo <...> quality of the placebo" should find its place in Clinical trial or Clinical endpoint or Treatment and control groups                                                                                                                                                                                                                                                                                                                               	Again, no it shouldn't, because it's extremely important to understand in order to make good use of the table it precedes. Someone without a comprehensive understanding of the term NNT would certainly be at high risk of thinking the only kind of control is a placebo, which is also exclusively what the section said before you reverted my work. Even readers who have read a number of academic papers documenting clinical trials would probably have seen the term "placebo controlled" in nearly every one. It is absolutely critical to the understanding of NNT to know that an NNT of 10 does not indicate a treatment is ineffective in cases where the control is an existing, effective treatment. AND it just so happens this EXACT scenario plays out in the table in this section. Not every reader has the incredible mastery of all epidemiological knowledge that you do, and not every reader want to open 6 different articles to understand one concept.
Repeating the same information again and again and again does not make things clear. It makes reader annoyed that they have to constantly skip over the same ramblings.                                                                                                                                                                                                                                                                                                                                         	You are wrong. Please learn literally anything about the science behind education or memory formation then get back to me. Repetition, especially when given in the form of similar information written in different ways, is without a doubt the best way to ensure understanding and retention of a concept. You just don't know what you're talking about.
Finally, if you forgive me, your contribution is not of high quality.                                                                                                                                                                                                                                                                                                                                                                                                                                           	No, I will not forgive that. There are a hundred much less rude ways of saying the same thing. If you were correct I'd be fine with it, but you aren't.
You write a sentence 'There are a number of factors that can affect the meaning of the NNT". What would you expect in a following sentence? I would expect an elaboration on these factors. Instead, you continue with "The treatment may be a drug in the form of a pill or injection, a surgical procedure". Why? How pill vs injection vs surgical procedure alter the meaning of NNT?                                                                                                                       	I'm sorry, do you know what NNT is? Did you read what I wrote literally right after the item you quoted? The route of administration, which is what "pill vs. injection" describes, IS A FACTOR affecting the meaning of the NNT. For example, the standard treatment is a pill consisting of a racemic formulation of a drug, and the experimental treatment is a subdermal implant that slowly releases the same drug, but in the form of the pure dextrorotatory enantiomer. Should the NNT be very high or negative, it is vital to know by what method the drug is delivered, as without this knowledge one might think the pure enantiomer is either not much more effective than the racemic mixture or less effective than the racemic mixture, when in fact it may be that the pure isomer is significantly more effective but the subdermal implant is not an effective mode of drug delivery. You are absolutely dead wrong on this which you would have realized if you weren't so focused on proving me wrong and instead used that energy to determine the truth and relevance of the actual information.
You write "The following examples", and follow up with "In this example".                                                                                                                                                                                                                                                                                                                                                                                                                                       	Wow, well there it is. There's the thing that justified REVERTING the edit instead of changing or deleting ONE SENTENCE. It's pathetic how little you care about actually improving the quality of the article compared to making sure you control every detail of all epidemiology articles.
Your text contains too much boilerplate such as "depending on the situation", "or many other possibilities", "The following examples", "In this example", "it is important to understand", "This is typically a type", "which may be a reduction or halt in worsening of the condition, an improvement in the condition, or an outright cure of the condition.".                                                                                                                                                	I fail to see how you can possibly call your last quote "boilerplate". Please point me toward the numerous uses of that exact wording elsewhere on wikipedia. No, nevermind, why don't you instead EDIT the phrases you don't like INSTEAD OF REVERTING THE ENTIRE THING?
You make strong claims without any citations, such as "This <...> type of study that would occur only if <...>", "Prospective studies produce much higher quality evidence <...>"                                                                                                                                                                                                                                                                                                                               	First, your convienient omission of THREE words in the first part of the quote via "<...>" provides a pretty important qualifier. The full quote reads "typically a type of study that would occur only if". As far as the other claim I made, if your competence in study design was as great as your arrogance, you'd know a prospective study is factually a source of higher quality evidence. It's called the scientific method. A study is only a true experiment if the scientist actually manipulates a variable, which is impossible in a retrospective study. If you think I'm wrong please tell me why, but I don't think you will because you have no idea what you are talking about.
In fact, you did not add a single citation                                                                                                                                                                                                                                                                                                                                                                                                                                                                      	Oh BOO-HOO cry me a river. If every edit that did not include additional citations was reverted wikipedia would be a wasteland. Do you know what you do if something is missing a citation? YOU ADD ONE. You do not REVERT the entire thing.
You redefine I_e and I_u differently from how they were defined in the article introduction.                                                                                                                                                                                                                                                                                                                                                                                                                    	No kidding?  Well, maybe that's because the definitions given in this section were TOTALLY WRONG. Why don't you tell me this original definition of I_e is correct, cause I'd love to see if you'll straight up lie:
Original: I_e is the probability of still having the disease after taking the pill (i.e. complement of the probability of being cured after taking the pill).
Wrong parts: I_e is the probability of *still having the disease* after *taking the pill* (i.e. complement of the probability of *being cured* after *taking the pill*).
Seriously, do you understand these concepts? Because your idea that the article should be using the word "cure" in the definition of the term is absolutely ludicrous and wrong.
"You write "I_e is the probability <...> this is the inverse of the probability <...>". This is incorrect. Inverse of a probability is never a probability."                                                                                                                                                                                                                                                                                                                                                    	No, you are incorrect.
Here is the first definition of the term "inverse" from wiktionary: "Opposite in effect, nature or order." Not satisfied? Want to use the technical definition? Sure, here it is: "(mathematics) Having the properties of an inverse; said with reference to any two operations, which, when both are performed in succession upon any quantity, reproduce that quantity." 
An action which may produce multiple events is repeated 20 times. Event x occurs 6 times, and other events occur 14 times. 
Probability of event x: 0.3. 
Method of calculation: 1.0 minus probability of "not x". 
Calculation: 1.0 - (14/20). 
Inverse: 1.0 - 0.3 = 0.7. 
"Inverse of 'not x'" calculation: 1.0 - 0.7 = 0.3.
Repeat the two operations ad infinitum.
Hey genius, why don't you explain this to me, because clearly I am too simple minded to understand your advanced logic which goes beyond both the technical and non-technical definitions of the word.
Sentence "For simplicity, a low number of participants will be used, thought scientific studies almost always require many more." just appears out of nowhere in the second row of the table.                                                                                                                                                                                                                                                                                                                   	Out of nowhere, huh? Cause it would seem the me that the first mention of "ten" participants might warrant a one sentence explanation. Don't like how I did it? EDIT IT DON'T REVERT IT.
You write "Notice that, even though the treatment was effective in eight of ten cases (only one less than the previous example)", but the previous example had two out of ten.                                                                                                                                                                                                                                                                                                                                  	No, actually, you are wrong YET AGAIN. The incompetence is only surpassed by the arrogance.
Previous example: "...Nine improve with the treatment and one does not."
You write "This is because" and then give a definition of NNT. That's not helpful.                                                                                                                                                                                                                                                                                                                                                                                                                              	You again have no idea how to write for an audience other than yourself. The repetition of the definition is very helpful to convey the meaning behind an NNT of -10, which counter-intuitively does not mean "really bad", as many readers might assume without the clarification.
If you decide to give another shot to this section, go ahead. But don't feel obliged, there are plenty of articles that would benefit much more from your attention than this one. I made an effort to clean up epidemiology measurements corner of the wikipedia (see my notes here https://en.wikipedia.org/wiki/User:Psarka/What_a_mess!), but ran out of steam. One page that is a particularly in need of love is Population Impact Measures. If you could try to sort that one out, it would be wonderful.	Listen close you disrespectful, incompetent, patronizing quack: why don't you give it ONE shot by EDITING the page rather than DELETING my hours of work. I don't care how much you want to rule over all epidemiology articles; that does not give you the unilateral authority to revert others' good faith work.
Sincerely,
Lumentex
--Lumentex (talk) 04:28, 12 November 2018 (UTC)
replies: text: I am sorry you feel this way. Do as you wish. Psarka (talk) 05:27, 12 November 2018 (UTC)
thread_title:  Reversion of Psarka's Reversion 

message: Hi Lumentex, 
I'm sorry, but I'm reverting your edits. Reading your message "Completely rewrote this section to correct many inaccuracies and greatly increased clarity of explanations. DO NOT REVERT WITHOUT THOROUGH EXPLANATION OF REASONING." I get the feeling that you are very emotional about your additions, but also that you had a hunch that they will get reverted. What made you think that? Did you saw some weakness in your text when you wrote it? 
Or maybe you thought that inevitably some evil guy will show up to destroy your valuable effort? If so, I'm afraid that no matter what I write, you already made up your mind and will curse me to hell.
Well do that, while I will try to do my best explaining my point of view in the politest and most constructive way I can. Here I go.
First you did not correct many inaccuracies. If you read the old version of that section generously, you will see that all the numbers and notions are accurate. The text is quite poor, I agree, but accurate. 
Second, your explanations made the 'Interpretation' column less tricky to understand, but are very verbose. I would like to try to find a middle ground between the two versions.
Your other additions are valuable, but they should find their place in different articles. Why? Take a look at the table at the bottom of the article. NNT is one epidemiological measure out of 25(!). All the discussion in this article should be focused on the NNT itself, and not the broad context of epidemiology. 
When I think about the article such as NNT, I imagine a reader that wants to quickly become familiar with the terminology of epidemiology measurements. So they click around and try to understand the differences between the measurements and their usage. My goal is to provide them this understanding as painlessly as I can.
That includes not burdening their brain with extraneous information that they could easily find in a dedicated article. In particular:
* Sentence "The treatment may be a drug in the form of a pill or injection, a surgical procedure, or many other possibilities" should find its place in Treatment and control groups or Clinical trial
* Chunk of text "This is typically a type of study <...> but are much more difficult and time-consuming to perform" should find its place in Clinical trial
* Chunk of text "The control group may receive a placebo <...> quality of the placebo" should find its place in Clinical trial or Clinical endpoint or Treatment and control groups
Repeating the same information again and again and again does not make things clear. It makes reader annoyed that they have to constantly skip over the same ramblings.
Finally, if you forgive me, your contribution is not of high quality. Consider the following things that caught my eye:
* You write a sentence 'There are a number of factors that can affect the meaning of the NNT". What would you expect in a following sentence? I would expect an elaboration on these factors. Instead, you continue with "The treatment may be a drug in the form of a pill or injection, a surgical procedure". Why? How pill vs injection vs surgical procedure alter the meaning of NNT?
* You write "The following examples", and follow up with "In this example".
* Your text contains too much boilerplate such as "depending on the situation", "or many other possibilities", "The following examples", "In this example", "it is important to understand", "This is typically a type", "which may be a reduction or halt in worsening of the condition, an improvement in the condition, or an outright cure of the condition.".
* You make strong claims without any citations, such as "This <...> type of study that would occur only if <...>", "Prospective studies produce much higher quality evidence <...>"
* In fact, you did not add a single citation
* You redefine I_e and I_u differently from how they were defined in the article introduction.
* You write "I_e is the probability <...> this is the inverse of the probability <...>". This is incorrect. Inverse of a probability is never a probability.
* Sentence "For simplicity, a low number of participants will be used, thought scientific studies almost always require many more." just appears out of nowhere in the second row of the table.
* You write "Notice that, even though the treatment was effective in eight of ten cases (only one less than the previous example)", but the previous example had two out of ten.
* You write "This is because" and then give a definition of NNT. That's not helpful.
If you decide to give another shot to this section, go ahead. But don't feel obliged, there are plenty of articles that would benefit much more from your attention than this one. I made an effort to clean up epidemiology measurements corner of the wikipedia (see my notes here https://en.wikipedia.org/wiki/User:Psarka/What_a_mess!), but ran out of steam. One page that is a particularly in need of love is Population Impact Measures. If you could try to sort that one out, it would be wonderful.
Sincerely,
Paulius
Psarka (talk) 22:02, 11 November 2018 (UTC)
thread_title: Reasons for reverting edits by Lumentex

message: as a random medical student with no experience with editing or contributing to wikipedia...this article makes a very simple concept wildly confusing and doesn't "fit" with the other 99% of articles I see on here.  I have no idea who the audience is supposed to be when writing on a topic like this, but seems like it needs to at least show the equation for people like myself that just want a quick refresh on NNT.  — Preceding unsigned comment added by 208.79.8.122 (talk) 23:35, 11 September 2014 (UTC)
replies: text: The equation is (and was for a long time now, I suppose) present. Psarka (talk) 22:26, 8 September 2018 (UTC)
thread_title: Random medical student

message: I have problems with odds ratio and relative risks being munged as they presently are. Why not present the OR=1/6 and the RR=1/4 as different measures? Johannes Hüsing (talk) 09:34, 18 April 2008 (UTC)
replies: text: They are no longer munged. Psarka (talk) 22:27, 8 September 2018 (UTC)
thread_title: OR and RR

message: --Hey. I have no idea how to edit a table, but I think the worked example table could use a little    --clarification. If you agree, could you make the change?
--CER 	control event rate 	= events / subjects in control group 	
--EER 	experimental event rate = events / subjects in experimental group 	
--"Events" should be stated as "events in control group" and "events in experimental group", --respectively. Using "events" alone makes it sound like it's using the total events between groups.   —Preceding unsigned comment added by 76.69.33.145 (talk) 22:08, 4 February 2008 (UTC)
replies: text: Just go to http://en.wikipedia.org/wiki/Template:ARR_RRR_worksheet and edit away... ;-) T.pienn (talk) 23:44, 19 January 2009 (UTC)
replies: text:  I suppose this was resolved some time ago. Psarka (talk) 22:31, 8 September 2018 (UTC)
thread_title: CER and EER

message: ---I changed attributable risk in the table to EER-CER (before it was listed as EE/[EE+CE] - EN/[EN+CN]).  Anyway, I think it would be a good idea to get rid of attributable risk all together, since it is just a synonym for absolute risk increase.  Anyone have any objections? Crackles (talk) 21:40, 24 May 2011 (UTC)
replies: text:  Attributable risk stuff is now fixed in accordance to the dictionary of epidemiology. Psarka (talk) 22:31, 8 September 2018 (UTC)
thread_title: Attributable risk in the table

message: I took out this example:
:the drug gabapentin, frequently used for neuropathic pain, only gives appreciable symptom relief in about 33% of all cases; the NNT is therefore 3.
I think we need to know how often the pain goes away without treatment before we can compute the NNT here. NNT always depends on quality of the drug and likelihood of the defined endpoint without the drug. For example, if 10% of patients get better by themselves, then the NNT would be slightly bigger than 4. AxelBoldt 22:43, 30 May 2005 (UTC)
replies: text: I simply added a number from my own experience. I should have sourced it from the Bandolier pain site. The NNT is not affected by spontaneous improvement. JFW | T@lk 08:32, 31 May 2005 (UTC)
replies: text: From reading the Bandolier article, I believe NNT is affected by spontaneous improvement; in fact their first migraine example explicitely compares a placebo control group's outcome with the treatment group's outcome. With treatment 5% recur,  without treatment 30% recur, so the NNT is 1/(30%-5%)=4. AxelBoldt 19:58, 31 May 2005 (UTC)
replies: text: Number needed to treat refers to the number of individuals that need to be treated to appreciate a beneficial result in addition to those in whom the result would be observed without the treatment.  It is derived in studies which have endpoints, therefore the endpoint for the outcome is implicit.  The statement "drug x provides relief in only 33% of cases" isn't sufficient to determine a NNT.  You need data on how many subjects got relief without geting drug x.  See the difference between a case-control study and a cohort study.Bakerstmd 03:33, 25 May 2007 (UTC)

text: Shall we find a better example? It seems you're correct about the spontaneous recovery rate, but spontaneous recovery rate is subtracted from the response in the treatment group before calculating the NNT. JFW | T@lk 01:49, 2 Jun 2005 (UTC)
replies: text:  As I see, better example was found. Psarka (talk) 22:33, 8 September 2018 (UTC)
thread_title: Take out an example

message: Although I understand the concept of NNT, this article still is rather opaque to me.  Probably also to many other readers.  So, how about making it more concrete for the reader by adding links to other Wikipedia articles on applications of NNT?  Also edit those articles to include the NNT data. --Una Smith (talk) 05:07, 1 April 2008 (UTC)
replies: text: This search shows a moderate-sized list of articles linking to NNT.  Some of them might be appropriate, although the few I checked tend to mention it in passing, instead of explaining it.  WhatamIdoing (talk) 05:51, 1 April 2008 (UTC)
replies: text: Good idea.  Looking at those links, I find inconsistent usage:  NNT is expressed as "1/N" or as "N". --Una Smith (talk) 06:02, 1 April 2008 (UTC)

text: The article already gives examples. We'd be better off providing more examples rather than using other content elsewhere (which may change) to illustrate our points. NNT is a number larger than on 1 by definition, so 1/N probably refers to 1/ARR (absolute risk reduction). JFW | T@lk 07:49, 1 April 2008 (UTC)
replies: text:  Marking this as resolved, as article has plenty of examples, and there is no "N" anymore. Psarka (talk) 22:42, 8 September 2018 (UTC)
thread_title: Let reader choose examples

message: Above, JFW says "NNT is a number larger than on 1 by definition" but I don't see that in the article.  On the contrary, the article Derivation section defines NNT as 1/(pB - pA) which looks like a number smaller than 1.  And pB - pA in the Derivation is ARR in the Worked Example.  It is possible for ARR to be greater than 1, in which case NNT would be smaller than 1.  The Derivation is incomplete.  Also, the Worked Example has an internal inconsistency:  it states that OR is both 4 and 0.25.  Finally, I find it more helpful to give a series of abstract equations first in full, then with numbers plugged in, rather than in a sketch parallel as in the table format. --Una Smith (talk) 15:49, 1 April 2008 (UTC)
replies: text: The NNT is computed as 1/(pB – pA) which is in fact "a number larger than 1 by definition" - because pA and pB are probabilities measured not as percentages but as decimals (of one) - and 1/(decimal-of-one) is always "a number larger than 1 by definition".  It is also not possible for ARR (this is not the relative risk, but the difference between those pair of decimals) to be greater than one. You are correct about the OR, it is confusing the way that it is both 4 and 0.25 (in my opinion, I prefer 0.25 here, but it should not be written as .25 as the decimal then is hard to spot). I always prefer tables or bullets above prose when a list of technical things w/numbers or w/attributes are being described, and I think that is the case here; however, I do think that this table could be a little more descriptive; I only wish I had more time but hopefully this helps...io_editor (talk) 23:49, 1 April 2008 (UTC)
replies: text: Chiming in to agree with io io regarding the math and the use of a table. I'm thinking that the prose leading up to the table could be "de-condensed" a bit. Antelantalk 01:50, 2 April 2008 (UTC)

text: Progress!  If pA is greater than pB, 1/(pB – pA) will be negative, so the absolute value of NNT is still greater than 1 but the sign will be negative rather than positive.  I prefer something between prose and the current table, namely blocks of "math" prose a la Diophantine equation.  The syntax is very similar to LaTeX, which I can do. --Una Smith (talk) 02:05, 2 April 2008 (UTC)
replies: text: Yes, what you say technically is true, but it is generally meant in the context of drug v control (or placebo), and (usually, but not absolutely always!) it is known in advance that one should be greater than the other. As to your example, while I love the huge font, in my work I like ready-reckoner stuff like tables (plus my eye-sight tires) - maybe combine best of both worlds or ask Antelan...io_editor (talk) 02:36, 2 April 2008 (UTC)

text: Can we add a sentence that says if the treatment has the opposite effect (eg, people who take a drug to prevent heart attacks are unexpectedly more likely to have an MI than the untreated group), then you'll get a negative/nonsensical number (that is, a number smaller than zero)?  I'm not sure that I can make what's clear in my head be sensible in words.  I strongly support including the equations.  (Please don't tell my math geeks.)  WhatamIdoing (talk) 06:13, 2 April 2008 (UTC)

text: Yes, but you're talking common sense, and I'm talking math.  1/(0.5-0.75) = –4, even if that doesn't mean anything in the real world.  Also, there's a divide by zero problem if there's no difference between the two groups.  I think this article should tell readers how to interpret these two cases.  WhatamIdoing (talk) 01:56, 4 April 2008 (UTC)
replies: text: I agree. --Una Smith (talk) 02:01, 4 April 2008 (UTC)
replies: text: Perhaps we should merge number needed to harm into this article, and mention that although the equations are identical, the label used depends upon the sign of the result. --Arcadian (talk) 00:00, 5 April 2008 (UTC)
replies: text: I would say needless, as JFW was implying. In such circumstances (no "treating" being done, and possible harm) the tool is not usable - its an irrelevant formula, and is not an NNT of any kind.io_editor (talk) 18:27, 5 April 2008 (UTC)

text: I would merge, perhaps into Number needed;  that would help to explain the bifurcation into harm and treat. --Una Smith (talk) 18:39, 5 April 2008 (UTC)
replies: text: The bifurcation is only in the formula. In actual pratice there is no chain-of-logic that leads to a bifurcation. I dont mind if you merge them, but I think it will be a waste of your time better spent - and quite difficult too. Other pages need real work. See you.io_editor (talk) 19:49, 5 April 2008 (UTC)
thread_title: Definition

message: I removed all the ELs on this article, none of them were, particularly relevant. I pasted them below.
*EBEM's Calculator for NNT
*What is an NNT? (Hayward Medical Communications)
*Number Needed to Treat (Centre for Evidence Based Medicine)
*Online Calculator for NNT (GraphPad Software) 
However, I do think these two are quite good. They should be worked into the article (inline references) instead of just dumped in the EL section. They should not stand on their own.
*Bandolier article on NNT
*Number needed to treat (Slate)
Chaldor (talk) 00:39, 21 September 2008 (UTC)
replies: text: I agree that some of these should be turned into proper refs.  However, a link to a calculator is exactly the sort of thing that external links is intended for; it's the classic example of "a unique resource beyond what the article would contain if it became a featured article."  Consequently, I have restored those links.  (If someone wants to figure out which one is "better", then perhaps a single link would be sufficient.) WhatamIdoing (talk) 04:27, 21 September 2008 (UTC)
replies: text:  I figured out which one is better (they all were the same, so I chose randomly), and hence removed the remaining ones, as suggested. Psarka (talk) 22:49, 8 September 2018 (UTC)
thread_title:  External links removed 

message: I'm of two minds about the inclusion of this link:
*"Treat me? The crucial health stat you've never heard of", Darshak Sanghavi, Slate Magazine, Sept. 26, 2006
On the one hand, it's a better WP:RS than WP:EL.  On the other hand, it "contain[s] information about the subject of the article from knowledgeable sources", and nobody's bothered to use it as a ref.  Perhaps in the interest of providing some accessible sources for further information, it's inclusion wouldn't be such a bad thing -- at least until someone decides to expand this article.  WhatamIdoing (talk) 20:24, 19 May 2009 (UTC)
replies: text: This link is no longer included. Psarka (talk) 22:51, 8 September 2018 (UTC)
thread_title: Slate again

message: Relative Risk is CER/EER 
Relative Risk Reduction is (CER-EER)/CER
Absolute Risk Reduction is CER-EER
Number Needed to Treat is 1/ARR
Or using a Punnett square, in which (a) has exposure & outcome, (b) has exposure but not outcome, (c) has outcome but not exposure, & (d) has neither outcome nor exposure:
RR is (a/a+b)/(c/c+d)
RRR is [(c/c+d)-(a/a+b)]/(c/c+d)
ARR is (c/c+d)-(a/a+b)
:It seems you´re incorrect or at least inconsistent: RR according to Punnett square is Experimental event rate to Control event rate, not hte other way around. T.pienn (talk) 13:47, 5 April 2014 (UTC)
replies: text:  Marking this as resolved. Psarka (talk) 22:54, 8 September 2018 (UTC)
thread_title:  Corrections/Explanation 

message: I was looking for online resources to help medical students study NNT and NNH for their board exams.  I was hoping this page could be a useful educational resource.
NNT is not a very complicated concept, but this article makes it into one.  It is not consistent with better-written Wikipedia articles on related topics(1).  Useful components of this article are buried amidst distracting and irrelevant concepts(2).  At least one example, should a reader attempt to replicate it themselves, appears erroneous or at least poorly explained(3).  There are a few content points that I think are reasonable(4).  I think it is unlikely that a reader would come away with an introductory working understanding of NNT after reading this article.
(1)Comparison to better-written articles: In general, the NNT article should probably be designed more similarly to it's better-written sibling article on "Number needed to harm."  A reader should be able to flip back and forth between the two pages and correlate sections at a glance.  This will make it easier to assimilate both topics and to highlight key differences between them.
(2)Useful components are buried amidst distracting and irrelevant concepts:
The key definition of NNT (namely, 1/[(P(B)-P(A)] or 1/"absolute risk reduction") is buried in the middle of the "Derivation" section.  This is, like, the punchline, folks.  It should be in large font on it's own line.  No-brainer.
Also: The third paragraph of the introduction describes the time-dependent nature of NNT.  It uses a simple mathematical example.  While it may be appropriate to mention the concept of time-dependence here, it doesn't make sense to get into math yet, when you haven't even defined NNT mathematically yet!  By doing this, the article gets ahead of itself, and the reader is likely to trip.
:"NNT values are time-specific. For example, if a study ran for 5 years and it was found that the NNT was 100 during this 5 year period, in one year the NNT would have to be multiplied by 5 to correctly assume the right NNT for only the one year period (in the example the one year NNT would be 500).[6]" - An underlying, dubious assumption here is that the successes and deaths are distributed evenly over the 5 years. This will be the case in some types of studies, but not in all.  — Preceding unsigned comment added by 84.215.102.2 (talk) 14:49, 2 January 2014 (UTC)
replies: text: I'm not an expert on the subject, but I am not surprised you found that it could benefit from a re-write. Let me know if you have any questions or run into any issues while you contribute to the article. Biosthmors (talk) 16:54, 5 March 2012 (UTC)
replies: text:  (1) NNT is currently in much better shape than NNH. (2) Formula is now in the definition, time based stuff is gone, and table has been improved. (3) Math error was fixed. BusinessWeek reference is indeed weird, but there seem to have been a fight over it already, so let's keep it. (4) whole article seems to be reasonable now. Psarka (talk) 23:01, 8 September 2018 (UTC)
thread_title:  Suggesting a total revamp of this article. 

message: It is interesting to note that while your article adopts the usual idea that the event is the undesirable aspect for each group, some sites, such as the Bandolier one, uses the desirable outcome as the event and subsequently changes the equations - might be worthwhile to point out.
Also some sites define ARD as the (absolute =modulus) and RD as the value that can take a negative value.  This can be useful in explaining simply that a negative NNT is in effect a NNTH, but obviously only if you use the ARD true and not the absolute value.  — Preceding unsigned comment added by 80.229.171.143 (talk) 11:42, 18 February 2013 (UTC)
thread_title:  positive as well as negative events 

message: I found this twice in this article:
: -10
It appeared to mean minus 10.  I changed it to this:
: −10
That is a proper minus sign.  If used to indicate one number subtracted from another it should be formatted like this:
: 20 − 10
with a blank space to its left and one to its right. 2601:2:4D00:27B:5582:2521:6AB:4186 (talk) 16:11, 8 October 2014 (UTC)
replies: text: Thanks! Psarka (talk) 23:03, 8 September 2018 (UTC)
thread_title:  A minus sign is not a hyphen 

message: How about another example with aspirin. The New York Times explains it in easy to understand terms. The Wikipedia article is written by statisticians for other statisticians. --Richard Arthur Norton (1958- ) (talk) 18:03, 6 February 2015 (UTC)
replies: text: I think one example is enough. Psarka (talk) 23:04, 8 September 2018 (UTC)
thread_title:  Asprin example 

message: How is time-to-cure or time-to-heal taken into account?  Suppose you have a condition that without treatment lasts from ten to twenty days, uniformly distributed, but the treatment shortens this period by five days for half of the patients and shortens it by a factor of two for the other half.  What would be the NNT in that case?  Vaughan Pratt (talk) 01:13, 19 February 2018 (UTC)
thread_title:  Time as a factor 

message: Right now, the caption for the first image is "Group exposed to a treatment (left) has reduced risk of an adverse outcome (grey) compared to the unexposed group (right). 4 individuals need to be treated to prevent 1 adverse outcome (NNT = 4)." Is that correct? From my understand, the adverse outcome would be colored in red as there are more "greys" in the (effective) treatment group. Or am I missing something? 2A02:908:D78:D1A0:3058:DE3D:230B:77EF (talk) 18:15, 23 February 2023 (UTC)
thread_title:  Caption wrong?