Talk:Continuous-repayment mortgage

Comments welcome

Comments and suggestions for improvement of this article would be most welcome.

Neil Parker (talk) 15:13, 30 April 2009 (UTC)

question. Are there any actual published references? DGG (talk) 14:51, 25 May 2009 (UTC)

Apparently there is - have added to reference section.

Neil Parker (talk) 10:34, 3 July 2009 (UTC)

Edit Tags on Main Page

Concerning the 'broom' and 'query' icons which have suddenly appeared at the top of this article. Some months or even years after it was originally submitted.

27 April 2009 - 17 June 2010 ≠ years ! Also, all articles here are intended to be in a state of continuous improvement efforts; so the new appearance of tags is by no means a bad thing. --Orange Mike | Talk 20:30, 17 June 2010 (UTC)

I checked the talk page (ie here). There is not a single reference to what this is all about. I checked the history page. No reference to person or moderator who placed the icons. I can certainly work on 'inline citations' but I do not recall them being a mandatory part of a Wikipedia article.

Could the relevant editor/moderator please clarify?

Neil Parker (talk) 08:11, 11 June 2010 (UTC)

Inline citations are how we work here; read WP:CITE for more details. A mere end-of-the-article dump of references is no substitute for proper footnotes, any more than they would be in a scholarly paper. --Orange Mike | Talk 20:23, 17 June 2010 (UTC)

And I don't mean to floccinaucinihilipilificate the effort clearly expended in the creation of proper inline citations since that notice was posted!

And as far as wikification is concerned: actual encyclopedia articles do not include "concluding remarks" and other stylistic quirks which makes this article read more like a student paper and less like an encyclopedic entry - see WP:MOS for more guidance. It would also help if there were more sources than just Beckwith iteratively recurring. --Orange Mike | Talk 20:27, 17 June 2010 (UTC)

The inline citations can certainly be tidied up but the point is they should demonstrate quite conclusively that the 'original research' tag is not applicable and that the requirement for inline citations has been met.

Once the core requirements of edit tags have been met, I think it is reasonable for a contributor to expect they be removed. That does not preclude further improvements - I have always indicated comments/suggestions would be most welcome - but I believe the article's talk page (rather than ongoing edit tags on the main page) is the appropriate forum for these.

Neil Parker (talk) 13:32, 20 June 2010 (UTC)

Re 'jargon'. Please elaborate.

Re 'notability': mortgage loans are financial 'bread and butter'. So I would imagine that mathematics pertaining to mortgages would also be of some relevance.

Neil Parker (talk) 15:18, 21 June 2010 (UTC)

As to "jargon": that is the term used in the template. This article uses mathematics at a level above the comprehension of the typical reader here.

As to notability: according to the article, this is a fictitious theoretical construct, and thus of only theoretical interest, and only to those in a tiny specialized field. Such a gedankenexperiment is not necessarily notable in the real world. --Orange Mike | Talk 15:27, 21 June 2010 (UTC)

No doubt articles such as those on the Laplace Transform and also on the Linear_differential_equation also contain "mathematics at a level above the comprehension of the typical reader". That does not 'per se' invalidate the articles appearing in Wikipedia.

Please exercise caution when using double adjectives such as 'fictitious theoretical'. They are most certainly not synonymous. I do not think a reputable journal such as JFQA would be publishing anything 'fictitious' or - for that matter - anything that is relevant only to a 'tiny specialized field'.

Struck the word "fictitious", as you have a point there; my intention was to clarify that this is a purely theoretical concept, not something existing in real life. --Orange Mike | Talk 16:30, 25 June 2010 (UTC)

Although I am not particularly happy with your edit tags they have been helpful in so far as they have resulted in improved referencing detail. I am currently engaged in further research locating secondary sources - there is actually quite a wide body of material available.

Accordingly I request that we keep this discussion constructive and aim (at the end of the day) to produce an article worthy of Wikipedia's well established reputation as an open and freely editable encyclopedia.

(talk) 07:45, 22 June 2010 (UTC)

Introduction

The introduction has now been comprehensively re-written. It begins by explaining the mathematics of an ordinary mortgage and then goes on to explain - in minute, if not indeed 'infinitesimal' detail - the corresponding mathematics of a 'continuous repayment' mortgage.

Jargon

I think this tag is inappropriate if what is actually meant is that (in the editor's opinion) the Mathematics is beyond the level of the ordinary reader. Jargon/Mathematics as a juxtaposition is in the same league as fictitious/theoretical. Mathematics is a well established category on Wikipedia and this article has been allocated accordingly. The 'ordinary reader' cannot be expected to (completely) understand the wide range of Maths related articles on Wikipedia but that doesn't mean we need to sweep them all away! What we can do is try to make the Maths as simple as possible so that as wide a range of readers as possible can understand it.

Constructively I think a lot could be done to tidy up the Maths so that we deal only with core aspects of the topic. So it would be good if the Maths could be subjected to a rigorous critique. This does not have to be done by any kind of specialist - the only requirement would be a basic understanding of differential and integral calculus and some background in the mathematics of finance. For the record I did in fact request one of my sources to read over the article. He obliged and suggested some improvements which were implemented - these should be acknowledged but I'm not sure how? Please advise.

Notability

It should be clear that the mathematics in this article is mainly related to the concept of a 'continuous annuity'. A Google search on this term will reveal any number of related articles/books which deal with the same topic. So - if anything - a case could be made for renaming/reshaping this article to 'Continuous Annuity' or just use Beckwith's title 'Continuous Financial Processes'. Otherwise if secondary sources are what establishes 'notability', there is no shortage thereof.

General

Thanks for the edit tags - they have certainly resulted in a lot of interesting research into secondary sources and - hopefully - overall improvement in the article's presentation. However please do revisit the tags in light of the above. Tags cannot just be applied and left indefinitely otherwise they become totally meaningless.

Neil Parker (talk) 08:05, 2 July 2010 (UTC)

Introduction

Have to say I have some misgivings about the introductory definition. Point is we cannot really define a CRM until we first define an ordinary mortgage. So that is why the 'order of operations' was as it was. Also it's not ideal to repeat the same thing twice in fairly short succession.

Continuous Compounding Reference

I don't really think there's any rationale for Wikipedia to become incestuously self referencing if I may put it that way. When researching this topic I looked at a number of online sources explaining this topic and chose the one I thought was best which I think is well within the spirit of a freely editable encyclopedia. In this particular instance it wasn't Wikipedia although I have elsewhere quite happily used Wikipedia references.

Neil Parker (talk) 18:36, 6 July 2010 (UTC)

Citations

With reference to comments below, I request further opinion on whether or not the criteria specified in the currently applied 'notability' and 'wikify' tags have been satisfied or not. And in either case, any suggestions for improvement would be most welcome. Thanks.

Neil Parker (talk) 08:21, 20 July 2010 (UTC)

Secondary sources have now been supplied as per criterion in notability tag.

Citations were stylized as per WP:CITE. The manual of style does allow for relevant footnotes but where possible the text of footnotes has now been incorporated in the main article.

Please detail exactly which citations "are still unclear". Also which Maths terms need links.

Thanks

Neil Parker (talk) 13:33, 12 July 2010 (UTC)

General comments

With regard to notability, I like the idea of renaming this article "continuous annuity" and broadening the scope. I inlined a few more references to make it clear which text they were supporting. The article seems to be sufficiently wikified, so I have removed that tag. But the intro is clearly too technical, so I added that tag. The section before the table of contents should be an accessible summary of the article; see Wikipedia:Lead_section#Introductory_text as linked from Wikipedia:Make technical articles understandable. I think the specific problem here is that that intro launches right into complex equations. Even if pushed later in the article, things like "end of term balancing equation" and "k" are not explained. The intro should be a summary of the rest of the article. In this case, describing the concept in words and graphs which compare it to non-continuous annuities would be very helpful. An accessible section describing the applications, invention, history, etc. of this concept should be presented before the much less-accessible math-heavy sections. -- Beland (talk) 16:17, 20 July 2010 (UTC)

Many thanks for your suggestions above - I hope however you will not consider it untoward for me to 'comment on the comments' !

I have thought about the name change issue and what I think there is that in terms of general practicality, the most common and well known use of annuities is in the repayment of mortgages and that is why I have chosen to focus on that particular aspect of the major supporting reference in JFQA. Otherwise the JFQA article does indeed deal quite comprehensively with 'continuous financial processes'. I could trot out the whole thing more or less 'verbatim' but that would quite rightly be dismissed as plagiarism. My task as I see it is to explain the concept within a context most readers will be familiar with. However as you go through the article, you will see that it does in fact deal with other annuity based applications such as the sinking fund.

We have already been through a process of trying to sort out the introduction which originally did start out as a summary of the whole. But the complaint was I had not explained what a 'continuous repayment mortgage' was and how it differed from a conventional one. So the intro was completely re-written with that in mind. This article is undeniably a technical/mathematical one and it has to start somewhere. That start point is a slight variation on a present value equation (commonly used in conventional mortgage calculations) which can be found in any number of school text books and - certainly in this country (South Africa) - on the standard school Maths formula sheet. I can certainly cite such even from the existing reference sources (Glencross). So I don't think it's quite fair to say we are launching right into complex equations. The Maths Dictionary link gives a very clear English language explanation of a continuous annuity - leading from there I explain (with some relatively straightforward Calculus) what that means in respect of modifying the standard present value equation.

Wikipedia has any number of technical/mathematical articles (eg on the Laplace transform). You can't expect non technical readers to understand these in any depth - this is no more or no less true for this particular article. And if I use notation such as the summation symbol or integration symbol, I do expect readers to know what these mean inclusive of the start and end values (k=1, k=n or t=0, t=T) which are in fact part of the associated Maths formula template. Finally in the lead-up to the first equation I do explain in English: "at which time the original loan with accumulated interest equals the sum of fixed payments and their accumulated interest". The equation then presents this as an 'end of term balance'.

Neil Parker (talk) 09:19, 21 July 2010 (UTC)

Derivation of time-continuous equation

Please insert commas between variable definitions in the first sentence to eliminate ambiguity. — Preceding unsigned comment added by 195.251.124.94 (talk) 08:06, 4 February 2012 (UTC)

Image is really stupid

The photograph of molten gold being poured in a foundry as an illustration of "cash flow" is a terrible pun at best, and outright useless and misleading at worst. It does nothing to illustrate the concept of "cash flow" and has no relevance to the article. Get rid of it. — Preceding unsigned comment added by 76.126.137.32 (talk) 04:47, 4 December 2012 (UTC)

Disagree totally. Molten gold is a very good illustration of literal cash flow as envisaged in the theory of this article. I would also appreciate it if the tone of the criticism could be a little more constructive - I didn't spend time investigating and trying to convey as best as possible the theory behind continuous annuities only to be called 'stupid' by some unsigned. Worse still not to have been consulted concerning the pulling of that picture by a Wiki 'editor/moderator' who should perhaps have a better understanding of the subject material. --Neil Parker (talk) 12:21, 17 December 2012 (UTC)

Gold pour picture

I want to make it clear I have no 'ideological' attachment of any kind to the 'gold standard'. I did not even know such 'ideology' existed. So 'pov push' (whatever that means) on gold standard means nothing to me.

Concerning the article itself the graphic is there to illustrate as best as I am able 'literal cash flow' which is the logical extreme of indefinite shortening of a loan repayment period. We pose (and analyse) the question as to what happens if that period (traditionally a month) is shortened - bi-monthly, daily , hourly etc.

--Neil Parker (talk) 16:41, 23 June 2013 (UTC)

In addition to the argument put forward previously by User:76.126.137.32, with which I fully concur, the use of gold "flowing" as an example of "cash flow" is really misleading. First because gold is not "cash" in an economic sense in most modern economies. Second because it is not a "flow" in the sense of economic Stock and flow either. If you didn't mean it as a subtle gold standard POV push, then I apologize for assuming you did. However, that mistake on my part does not change the fact that the image is at once misleading and irrelevant. -- Selket ^Talk 00:54, 24 June 2013 (UTC)

I think the basic problem here is that you are not thinking in terms of the principles on which this article is based. You have a neatly boxed idea in your head about what 'economic cash flow' is and because a gold pour doesn't agree with that and you can't be bothered to think 'out of the box' your are dismissing my image as "misleading and irrelevant". Let me assure you - it is neither. 'Cash flow' in the context you are familiar with is a metaphor. Of course cash does not flow - it is not a liquid. But what I am asking readers to imagine in the context of this article is indeed as close as we can get to the idea of a real liquid with real value that does actually flow. That is why I have indicated 'literal' cash flow to be distinguished from the metaphor.

Take petrol for example. Do you agree that it has value per litre ? That if you pour petrol into a tank at a certain flow rate (litres per second) for a certain time you will pay a certain amount dependent on flow rate, value per litre and time:

Fixed flow rate (litres per second) x Value per litre x time = what you pay. C = kt. k having units in value / second.

A gold pour is an exactly similar concept. You pour the gold into a tray and it accumulates value depending on how long the pour lasts for:

C = Ma x t as per the article (understand that unlike the gold (or petrol) pour, the time and flow rate are in years and value per year rather than in seconds and value per second).

The integration elements of such a pour are dC = Ma x dt and the integration (without any interest concept included) will trivially yield C=Ma x t. Now here is the point: we take each value element Ma dt and apply to it continuously compounded interest from the time it appears (t) till the end of the 'pour' at time T.

dC = Ma x e^r(T-t) dt.

In such manner we derive the basic integrating element on which the entire article is based. I need readers to understand the 'literal cash/value flow' concept as distinct from the metaphorical one. Perhaps this discussion will assist towards that end. If you are satisfied with my explanation, kindly revert your deletion of the gold pour or alternatively come up with a better means of illustrating the 'literal cash/value flow' concept.

I would point out (to you and your unsigned colleague) that the order in which this process ought to happen is that you first initiate discussion and then - if logic demands it - proceed with edits/deletions. Not hold a gun to my head by first deleting - on very speculative grounds - and then demanding an explanation from me just because you can't understand the relevant concepts or have some or other ideological 'hangup'.

I await your alternative explanation/illustration with 'interest'.

--Neil Parker (talk) 08:14, 27 June 2013 (UTC)

Your argument in favor of the picture I think reinforces my point about it being misleading and confusing. Gold in a liquid state does not increase in mass while it's flowing. There is no "interest" paid in extra physical gold or anything like that. Your second paragraph raises two important points. You say, that I am "not thinking in terms of the principles on which this article is based" and "You have a neatly boxed idea in your head about what 'economic cash flow' is and because a gold pour doesn't agree with that and you can't be bothered to think 'out of the box' your are dismissing my image as 'misleading and irrelevant'." If this is what you're trying to do, that is, write an article on new principles, then it's original research, which is not permitted on Wikipedia. I would also point out the policy on verifiability, and suggest you locate a reliable source equating continuous compounding of interest and flow of molten gold. Finally, throughout the article you seem to be conflating a mortgage and a loan secured by a mortgage. -- Selket ^Talk 15:30, 27 June 2013 (UTC)

Complaining about edits on an article submitted.

I got a message from Neil on my User talk page; since it now involves multiple people and the topics already discussed on this page, I though I'd move the discussion here for simplicity. -- Beland (talk) 04:03, 28 June 2013 (UTC)

---

Hi

I submitted the article Continuous-repayment_mortgage which has been on Wikipedia for a few years now and has been tidied up, aligned with referencing standards etc. You may recall making some suggestions for improvement yourself.

I want to complain about a very insistent editor User:Selket who keeps deleting a graphic which I included and which I consider to be a key illustration of a core concept developed in this article. He had some ideological issue with me promoting the 'gold standard' - I did not even know there was any such ideology as I pointed out to him. Then he started saying the image was "misleading and irrelevant" - worse he concurred with a previous (unsigned) editor who did the same thing and said the image was "stupid" - that is totally unacceptable. Whenever I try to revert the edits, he 're -reverts'. I have not allowed myself to engage further with any editing 'war' but have rather stated clearly on the talk page my reasons for including the graphic and requested him to restore it once he has enlightened himself as to the reason for it being there.

As a serious contributor on Wikipedia, I object strongly to this type of interference with my article. In my view the reasons given for deletion are primarily ideological ("gold standard pov push" - whatever that is) , are insulting ("misleading and irrelevant")and at the same time display an abysmal lack of understanding about the article's content. Could you please advise as to how I go about complaining so that this type of nonsense is prevented.

Thanks. --Neil Parker (talk) 12:01, 27 June 2013 (UTC)

I made two edits to the article over a week long period, and you appear to be confusing me with the IP poster who called your image "stupid." I did not. I'm not entirely sure why we're having this conversation here, but since we are, I think a quick review of history is in order. First I removed your image from the continuous repayment mortgage article. I did so because I believed it was irrelevant and misleading. The only reason I could think of for someone wanting it there was for ideological reasons. You reverted it and added a note on the talk page saying you weren't being ideological. I accepted that, and apologized, but I also laid out more substantive reasons why it doesn't belong on that article. After not receiving a response from you for over 24 hours, I reverted the deletion. You have now replied on the talk page and I'm happy to continue this discussion there. I'm not really sure why we're engaging other editors at this point.

It's also worth pointing out that your statement, "I object strongly to this type of interference with *my* article," really smells of WP:OWN. -- Selket ^Talk 15:14, 27 June 2013 (UTC)

Well, first of all, thank you both for your efforts to improve this article. Sorry if some other editors have been a bit sharp; I'm impressed you were able to share your motivations and reach a better understanding of at least what you are each thinking. Interpersonally, it's really easy to misunderstand what someone else is doing to an article when they're just an anonymous one-liner on the Internet...I guess that's the whole point behind Wikipedia:Assume good faith.

Selket is right that Wikipedia discourages ownership of articles. Instead, we encourage editors to be bold and make changes they think will improve the article, usually without asking anyone for permission. We write articles not for ourselves or our own reputations, but to selflessly help other people learn stuff. It can sometimes be a bit painful to watch the baby you have carefully constructed turn into something completely different at the hands of strangers - I've certainly had that happen to my articles and meta pages. But, keeping a low barrier to editing means we get a lot more useful contributions, and letting people from multiple perspectives and levels of knowledge pitch in (hopefully!) makes articles more neutral and more accessible to a broader audience without dumbing them down. When disagreements about changes arise, the right thing to do is to take it to the talk page as soon as possible after it becomes apparent there's a conflict. (And hopefully well before the three revert rule kicks in.) If agreement can't be reached, I find the best thing is to get more opinions until some sort of consensus or compromise emerges. You have already done exactly that, so as far as I can tell, this disagreement (which happens all the time on the project, trust me) is on its way to being resolved amicably without the need for disciplinary action against anyone.

To bring this discussion back to the article itself, I guess the current sticking point is this picture of liquid gold and whether or not it should be in the article. Personally, if I were trying to explain the concept of continuous annuity to someone who didn't yet understand it, I would not use this picture. It would be a cute tongue-in-cheek illustration for cash flow or market liquidity, but even there it's a bit of a stretch to argue it's serious enough for an encyclopedia article. As a literal analogy for continuous payment, I have to agree that the mathematics of transferring a liquid and making payments on a continuous annuity do not align well. As such, I would worry that making this analogy would be more confusing than helpful. I do like that you are thinking of visual ways to explain this concept. I think what would make a much more informative replacement graphic would be something like File:Compound Interest with Varying Frequencies.svg that directly illustrates the difference between continuous payments and discrete intervals. Seeing it on a graph-over-time like that makes more sense to me than imaging a pile of something changing over time, even if it is shiny and golden. So, my vote would be to leave the gold pouring image out.

Feel free to invite other editors to express their opinions (without canvassing of course) but given the nature of the disagreement and that three editors have opined against the pic and two of us have had the opportunity to carefully consider the detailed arguments in favor, I doubt the outcome would be much different. My advice would be to move on to something more fun, like adding something new to the encyclopedia, improving the article in other ways, or taking a brief wikibreak and finding some unwilling children and forcing them to experience the joys of nature. Whatever floats your boat!

Thanks for reading this long reply, Beland (talk) 04:03, 28 June 2013 (UTC)

I had an image which I considered relevant. A suggestion was made by anonymous (who called the image 'stupid') that it be removed. Editor Mike Orange concurred by removing the image. I reverted. Editor Selkert removed it again thus also concurring with the original suggestion that the image was 'stupid'.

It's very plain from what I've seen in the discussion above that none of Mike Orange, Selket or (now regrettably) Beland have any clue or understanding about why the image is there. What on earth is Selket saying that gold doesn't increase mass while it's being poured? We are talking about the mass of gold that is accumulating where it is being poured. I'm not going to waste any more time - suffice to say no use casting gold before the (ostensibly) wise. The continuous interest graphic is relevant to continuously compounded interest (the concept of which is deployed here) but that's not what this article is about. With due respect remarks about the image in question as a 'cute' or 'tongue-in-cheek' illustration are patronizing at best and at worst just another 'illustration' of a totally abysmal lack of understanding. Finally while I wrote the article I of course accept others may edit - are indeed encouraged to edit. But this nonsense originating from some anonymous calling my image 'stupid' is unacceptable as are the subsequent clumsy attempts to justify it still without even demonstrating a modicum of understanding as to why it is there in the first place.

--Neil Parker (talk) 15:39, 17 July 2013 (UTC)

I certainly agree it's not very nice for anonymous editors to call other people's work "stupid", and they shouldn't be doing that. I do see why you put it there in the first place. As for the lack of "understanding": Selket is mathematically modelling the liquid gold as the principal, where as you are taking it to represent both the principal and the interest, disregarding the fact that the amount paid back is larger than the amount borrowed. This is where the disagreement over the math and appropriateness of the image to convey the concept comes in. Given how hard it's been to communicate this, it's probably for the best the image has since been removed so readers aren't confused in the same way. -- Beland (talk) 06:09, 26 August 2013 (UTC)

I certainly don't agree with the use of the term "stupid" by the anonymous editor. That said: this is an encyclopedia article, not a PowerPoint presentation, and thus does not need illustrations such as this. I don't consider them encyclopedic or appropriate. --Orange Mike | Talk 13:40, 26 August 2013 (UTC)

@Beland: Oh dear, oh dear, oh dear - muddle, muddle and more muddle! The liquid gold models neither the principal nor the interest. It models the repayment 'stream' which (as payment frequency is increased indefinitely) becomes more and more akin to a literal liquid flow. Please give me at least some credit for having carefully read the source article, understood it and interpreted it correctly! To quote from the source article (Beckwith, R.E) "Monies paid into a fund in the financial world are paid at discrete – usually equally spaced – points in calendar time. In the continuous process the payment is made continuously, as one might pour fluid from one container into another,(my bolding) where the rate of payment is the fundamental quantity".

@Mike Orange: if you don't know what the illustration is about, then with due respect I don't believe you are in a position to determine whether or not it is'encyclopedic' or 'appropriate'.

However as a result of all the above, I have given some thought to what might be an appropriate alternative illustration. The idea of showing plots of compound interest applied at various (decreasing) time intervals is not a bad one. It just needs to be applied to the 'continuous amortization' process rather than to 'continuous compounding' which is adequately dealt with elsewhere in Wikipedia. I have such a graphic and I propose posting it in place of the 'continuous compounding' graphic which (as I've previously mentioned) is not really on the button here.

--Neil Parker (talk) 07:57, 12 September 2013 (UTC)