Replacing the homework policy 1b: what is our scope anyway?

Question

Abstract: Analyzing the data from the last replace-the-homework-policy question was inconclusive. So back to the drawing board, or really back to our starting point: what kinds of questions do we really want to see closed? In particular, what are better ways to characterize our actual reasons for closing questions where we currently use the "homework-like" close reason?

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Important note, because I guess this hasn't been clear in the past: the purpose of this series of posts is to come up with a brand new set of guidelines for question closure. We are not reformulating or tweaking or improving our current homework policy. We are replacing it entirely - that means we are getting rid of it and developing a new set of policies and close reasons, which will presumably make no mention of "homework" or "homework-like". Once this process is done, there will be no homework policy and no "homework-like" close reason.

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As some/many/most people are aware, we are in the midst of a long-term project to replace our homework policy with a new set of guidelines that better reflect what people actually consider on topic and off topic. In the first phase of this project, we collected some example questions and voted on whether they should be on or off topic, to help clarify the new guidelines we want to come up with. I also collected some opinions on various qualities of these questions in a separate survey. The goal was to try to find some correlation between the topicality of the questions, as represented by the score, and one or a few of the attributes, and that would tell us what are the main factors people consider while voting to close.

As it turns out... that doesn't work very well. I spent a long time tinkering with the data and basically what I found is that people's opinions vary widely, making it hard to draw meaningful conclusions. The first thing I checked was whether any individual factor from the survey correlated well to people's impression of whether a question was on topic. There were some correlations with physical context and interest, and to a lesser extent level and effort, and an anticorrelation with tediousness (this means that within our data set, people are more likely to consider questions which concern tedious calculations on topic), but none of these are very strong.

I also looked at whether a combination of factors could provide a good discriminator between on-topic and off-topic questions, in a couple different ways. First, a partial least squares regression to test whether some linear combination of ratings would be able to accurately predict the scores of the questions, but that didn't work at all.

The other approach, which I think best mirrors how the actual close-voting logic works, is to find a set of factors such that the on-topic questions rate highly on all factors but each off-topic question rates low on one or more of them. This plot shows the mean minus one standard deviation¹ of the distribution of ratings for each of the highest-score (most clearly on-topic) sample questions:

and this is the equivalent, showing mean plus one standard deviation, for the lowest-score (most clearly off topic) sample questions:

I was looking for a group of one or a few rating factors such that the corresponding columns in the top plot are all red or white, and the columns in the bottom plot between them contain one blue cell for each question. Unfortunately, there is no clear candidate. I even had the computer go through all possible combinations of rating factors to test them out, and all the combinations in which the on-topic questions rank high have large uncertainties in the off-topic questions, and vice-versa. The one factor that does keep popping up is "check-my-work-ness", which may be an indicator that people agree that questions just asking us to check work are off topic and that we do okay at identifying which questions those are.

Anyway, the point seems to be that none of the factors in the survey are a particularly good proxy for how we decide whether questions are on or off topic. (And remember, we're mostly talking about questions which we currently close or might consider closing using the homework-like reason.) So before we proceed, I want to throw the question back to the community in a revisit of the question where I first tried to collect possible close reasons. In light of all the discussion and analysis we've done since then, when we choose to vote to close questions as homework-like, what reasons do we actually have in mind? Or, how could we do more research to work this out?

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¹The idea is to identify clearly on-topic questions as those for which something approximating the 68% confidence interval of the score is entirely positive, indicating a high score and clear agreement on that score. It's basically the same idea underlying e.g. the reddit scoring algorithm.

Answer 1

Determining how to redefine this policy is a tricky subject. Not only because of the varying and contradictory opinions about it, but also because we seem to be tackling the issue from the middle. Admittedly, in football, that is a sound strategy, but in politics (and that's just what this is), it's often best to start from the beginning.

Before we get ahead of ourselves, we should step back and officially answer some questions that I'm sure many of you will consider already answered. But until we know everyone agrees on them and knows our stance, we can't properly move forward.

This first question we need to ask ourselves is simply "What are the goals of this site?" What is it we want this site to represent? What are the ideals to which we should hold all of the content on this site? Should it be by physicists and for physicists? Should it be a place where people can learn physics concepts? Should it be a homework help site? Again, many of you may think this an unnecessary step, but when there exists so much disagreement concerning a policy, it makes sense to retreat to a position where we can all agree on something and build from there.

The second question we should ask ourselves is "How much freedom are we willing to grant users in deviating from the goals and ideals of this site?" If the site's goals are to make it a place for professional physicists to ask/answer about research-level physics, how much leeway should we give for users to ask more basic questions? This answer needs to be weighed with how much any amount of deviation will detract from the ability of our site to live up to the goals we agree on. It also serves to provide necessary background and understanding so that everyone can be on the same logical page moving forward.

Now we get into some of the more contentious questions. Most close reasons are easy to determine; the ones we need to decide on are the off-topic sub-reasons. So the next thing we must ask ourselves is "What types/topics/formats of questions would be actively harmful towards meeting the goals/ideals of the site?" This should be applied to questions at all levels. By determining what is actively harmful towards the proposed site goals, we can more easily determine what is off-topic. We should also take this opportunity to realize that the freedoms we established in question 2 may indicate sub-goals of the site and that it may be the case that some questions, which do not directly contribute to the primary goals, may be beneficial or detrimental to the sub-goals.

The last question we should be asking is "What commonalities in these harmful questions can be isolated as reasons to close a question as off-topic?" Here is the important step. This is a place to identify the important patterns in the questions we found to harm the site's objectives. We also should use this step to recognize any biases we have. For example, if we find that everyone is more lenient towards interesting questions, then we need to decide if policy should reflect this or not; allowing exceptions based on general interest or requiring that decisions be made with no regard to the popularity of the question. By approaching this from a standpoint of "Why are these questions harmful to the goals of the site?", we can more easily divine the set of rules that would prevent such questions. But, again, in order to do that properly, we need to have the answers to all the previous questions agreed on and made explicit. I would expect that reasons like the non-mainstream one will remain, but we may find that our homework-like policy never enters into it. We may also find that much of the misuse of some close reasons spawn from a general disinterest of users, and not from any rational source. That would, of course, be a worst case scenario; I'm just giving examples. At any rate, this step also needs to keep in mind how enforceable any close-reason can be. As we once discovered, closing a question purely because it is taken from a homework assignment is not very enforceable. All one needs to do is slightly reword it and claim it is a genuine curiosity. Furthermore, something like closing because a question is too tedious is too subjective to be adequate. Obviously, reasons should be clear, defined, and effective.

If I may jump back to the beginning of my post, we've been approaching this starting from the third question (David Z's thorough research). While I definitely see the appeal in this strategy and advocate it being a good first attempt, once this fails (as we noticed it did), we should go back and truly start from the beginning. It's a longer process that should help to create a more permanent solution.

Now, some of you may point out that I haven't actually done anything towards saying how we could answer these questions, nor have I suggested any way the home-work policy should be changed or researched. You're right. At the moment, I don't see much point in trying to directly address the homework policy, nor can I imagine a situation where we could conduct research and find a clear solution. And if I had included my own answers to the questions I presented, you'd all have voted on whether or not you agree with my answers to those questions as opposed to agreeing with the issue of whether or not the questions need to be addressed at all. Additionally, as demonstrated, people don't seem to have any one thing in mind when they use the homework reason, so the only way I know to fix that is to establish a basis that gets everyone on the same page.

We seem to be building a house on sand and every time the tide comes in, we question why part of this house gets washed away and every time, we try to rebuild that section newer and better. Instead, I merely suggest we tear it all down and lay a proper foundation before attempting to build it back up. The tide may eventually erode the foundation, but at least it'll last a good while longer.

Answer 2

The current situation and its problems (yes, again)

In light of all the discussion and analysis we've done since then, when we choose to vote to close questions as homework-like, what reasons do we actually have in mind?

Taking your data, and indeed the continual disagreement in most past meta posts about this topic, at face value it appears that there is no single reason people close something as homework-like, showing that the current close reason is also probably more used as a proxy for a host of different reasons than what's actually written in the policy, or whatever would be actually written in the policy once we'd chosen one or more "main" reason to close something as homework-like.

This is an uncomfortable situations, and it also explains why this policy continues to be discussed (other than, say, the non-mainstream policy, about which there seems to be general agreement, and only dissatisfaction about its application in isolated specific cases). However, it also means that "replacing" the homework policy by the things it's used as proxy for is infeasible, because there's no agreement what it is used as proxy for.

I suspect this is because the policy was initially conceived to ban actual homework to stave off using the site as a cheating resource. This has two issues: How to tell whether something is "actual" homework, and what about good questions that someone could conceivably encounter otherwise, but that are assigned as homework in the case of the asker? So the homework policy mutated into the "homework-like" policy, looking at the content rather than the origin of the question. However, what exactly is "homework-like content" was, at least from some points of view, insufficiently (and somewhat contradictorily) codified in the policy post as such, which is argued e.g. in this meta answer.

That therefore the policy as written is actually not what motivates many closures is what triggered this whole debate, cf. the opening statement of Generalizing the homework policy:

However, it's not always clear whether a question fits this description just from its content. And if you track the questions that we actually close these days using the homework-like close reason, quite a few of them are likely not of an educational nature. Instead, we've taken to using the homework-like close reason on questions that simply ask us to calculate something without the original poster making an attempt at it.

A radical solution

Get rid of the homework close reason.

Yes, I mean that. I don't mean to imply that we should leave any of the question open that we currently close as homework-like, but this whole debate shows that "homework-like" is really just a proxy for a bunch of more specific close reasons, which would be more helpful to the people asking the question and more helpful to avoid arguments between reviewers over whether something is "homework-like", when the arguing parties really mean two different things by that word.

Unfortunately, we don't have enough slots for pre-generated reasons left to cover all of the partial reasons for closing as "homework-like". Fortunately, the "other" close reason allows for an infinite variety of close reasons, so we only have to decide which reason deserves to be in the pre-generated spot and which ones the reviewers have to type out.

We already have discussions on insufficient effort and "check my work" as close reasons. We have broad support for closing "tedious" calculations without context. There are upvoted arguments that being a conceptual question and showing effort, as in the current "homework-like" close banner, should apply to all questions.

Each of these discussions about policy, each of which covers a certain subset of why people want to close homework-like questions, is worth having. These are specific topics on which people can take a stand for or against, and we can sort out where the general community trend lies.

This discussion about the "homework policy", however, and about a catch-all proxy reason for all the actual reasons it encodes is not worth having anymore. It's too confusing, people are talking past each other, and we have both historical and analytical data showing a consensus is nowhere in sight. So let's just axe this reason and start having constructive discussions about more specific close reasons.

Answer 3

I agree completely with ACuriousMind's answer, so I won't go into that, but simply expand on what main reasons I see things being closed as (or should be closed as). These are of course just my opinions, and I would welcome explanation of disagreement in the comments.

Close Reasons

Not Enough Effort

I've seen much discussion about this one; however, I think it is important in a certain formulation. First, I think there are two situations where this is applicable:

1. Questions that would normally be considered "problems" where no work is shown, e.g. https://physics.stackexchange.com/questions/276675/motion-in-a-projectile-plane, https://physics.stackexchange.com/questions/276640/pressure-cooker-at-a-hill-station (this can be used on non-math work questions; it is more about showing your thoughts).
2. Questions whose answers are so blatantly obvious (I don't even mean Wikipedia-obvious, I mean even more blatantly obvious) that they are not worth answering, e.g., https://physics.stackexchange.com/questions/276508/what-is-internal-energy, or (hasn't been asked) "Why do rocks fall".

I do not think questions should be closed for this reason if they do not fall into one of those two categories. I mean, for example, that a question such as How to measure the inner diameter of thin tube (0.5mm to 2mm) should not be closed for not enough research effort. While it is a poor question, perhaps, and deserves a downvote, it should not be closed as "not enough effort".

The reason I think it is important that this reason is limited to these two categories is because of subjectivity. Most people can agree that questions falling into the two categories above should be closed, but there could be a lot of debate about another question that might have been otherwise closed with this reason.

Check My Work

This should definitely be a close reason. I have seen many questions that could (and should) be closed with this reason (for example, https://physics.stackexchange.com/questions/276576/line-of-charge-passing-through-centre-of-a-charged-semicircular-rod). This seems to be one of the main categories homework-type questions fall into.

It is also worth noting that the check my work close reason should only be used for trivial calculation errors; questions about a conceptual mistake (for example, whether a certain formula is appropriate in a given situation) are on topic.

Purely Calculation

First, I'd like to point out that just because a question asks about math or includes math does not mean it is off topic! I say this because I have seen multiple questions that I would consider good, on-topic questions closed under the idea that they are "not conceptual". I'd solidly disagree with this.

This close reason is more for questions that are all math, or all "do my math for me". Tedious do-my-work questions would probably fall under this close reason (aka, calculate this for me questions). An example of a question that is on-topic (even with this close reason) in my mind would be Mutual $E$ force due to charged coaxial rings (though I am specifically referencing question #3 as listed, #2 is more a mathematics.SE question and #1 is a check-my-work question).

Ones that should be closed under this reason would include, for example, the question https://physics.stackexchange.com/questions/275704/angular-trajectory-of-body-moving-on-rim-of-a-carousel.

Note that if there is a more specific close reason, then one should use that. For instance, you could say there's some overlap between the check my work close reason and the not conceptual close reason. But obviously, if both are valid, the one that is more specific to the situation is the one that should be used.

Formulation

The specific formulation of whatever close vote reasons we pick will probably need to be hashed out in their own meta post. But, I'll just give a few starter definitions here.

For "not enough effort":

This question does not show enough effort. It either does not show the thought process that lead to the question (mathematical or otherwise) or the answer can be very easily found on the internet. As such it does not carry any value for future readers. See our [meta site][] for further guidance.

For "check my work":

This question appears to be about checking your work, and a trivial calculation mistake, not a physics concept. See our [meta][] for more guidance. Please also make sure that if it is about how to calculate something to try math.SE.

For "Purely Calculation":

This question appears to be outsourcing a calculation to the community without any broader context. Please ask about a specific concept, show work and explain where you got stuck, or provide more context. For more information, see [this meta post][].

(Please note that where I put [some text here][] I meant for a link to the definitive meta post to go there.)

Hope this helps, and any feedback would be appreciated!

Edit: I originally worded the title to the third possible close reason rather poorly, and changed it. The third close reason is meant for purely calculation questions, as the title says, and I'll be adding more examples of questions that would be closed under this reason soon.

Answer 4

Here is my take on the matter. First, let's think about what Stack Exchange Q&A sites are good for and what they are not good for:

• A Q&A site needs Questions, which can be answered in a concise fashion. There may be several good answers, but if a question needs books to be answered or many answers covering different topics (and thus many pages of answers), it's not a good fit.
• Questions that are an especially good fit are questions where there can be different angles from which to approach it so that many good answers can emerge. This also gives meaning to question ranking.
• Questions that spark discussions are a bad fit.
• The specific idea of Stack Exchange Q&A sites is that the answers to questions and the questions themselves should be interesting to a broader audience.
• If the questions are not interesting for very many people, they need to be of research quality.

In fact, as I see it, we have some tradeoff: If Q is the quality of the question in terms of how many people could answer it ("research quality") and A is the audience that can get some new understanding from the question, then the product QA should be large for good questions. This leaves room for conceptual questions about basic theories as well as high level and extremely specific questions about research.

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If we agree on the above, here is my take on what should be closed and what shouldn't:

Check-my-work: Questions like "Where is my mistake?" or "Did I do it right?" come in two flavours: The first questions make one of a few very common mistakes. Those mistakes are common, because they are based on a fundamental misunderstanding of the theory. They should be closed but could be reworded to ask a conceptual question about the theory, which is interesting for many people. The other type of questions are just algebraic/mathematical mistakes. There are a myriad ways to make mistakes and thus the answer to the question is mostly only interesting to the asker and it usually also is of bad "research quality".

--> Close as check-my-work. If you think there is actually an interesting conceptual misunderstanding in the question, rewrite it and/or leave a comment. Then the question can be reopened.

Really low research effort: Since most of the audience arrives by search engines, those people will actually do a Google search. If this will directly lead them to a Wikipedia article, what do they gain by coming here? So aside from the fact that low effort questions might disparage researchers from staying on the site, they should be closed because they don't actually have an audience: Why should you come here to get a link to the Wikipedia page you could already see in your Google search results?

--> Close as "low effort", if the question could be commented on by "What about this [Wikipedia/other well-known source that pops up if you type the question into a search engine] is unclear".

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Those are in my opinion the "easy" ones. Now come the "hard" ones:

(Low effort) problems: These are questions that essentially ask for the solution to a homework problem while providing or not providing own ideas. The problem with these questions is two-fold: a) if the asking party actually wants to understand the problem, you'd need to discuss with them --> that's not a good fit for Q&A, b) the audience for these questions is often only the asker him/herself (see "check-my-work" questions).

Defining a close reason such as "no sufficient audience" won't work and will only spark more discussion, as will "homework" ('oh, but that's not homework, I thought about this exercise myself'). One of the biggest problems is also that these questions are best answered by working with the person and asking questions and giving rough sketches and approaches - so they are just a bad fit anyway. This is particularly true for many questions where the author posts a lengthy and detailed list of her own failed effort. While those questions do signal that the author of the question doesn't just try to dump his problem on us, they are just generally a bad fit for Q&A sites.

--> One idea could be the following: Introduce a close reason "not conceptual" and apply it to any questions, asking for one solution to a problem where most variables come with numbers attached. This would allow questions asking about how to generally approach inclined plane problems where a set of parameters is given, but it would disallow questions asking about inclined plane problems with a specific set of parameters (for instance and angle of 45°). Having a rule like "A questions where a lot of variables are fixed is closed" would eliminate some of the ambiguity of the word "conceptual". It would also allow questions asking for different ways to approach some problem, which in my opinion is a valid conceptual question.

Pure calculations: Calculations are also difficult, because they can come at any level - and any difficulty. Most calculation questions are only interesting for the person asking them, so they should be off-topic.

But often when somebody reads a paper, he/she may stumble over some step in a calculation or some line of an argument that they don't understand. What about such questions? Now, often, we can refer those questions to math.stackexchange and be done with it, but often the questions may involve physical approximations and are better left here. Not understanding some equation in a paper is something extremely common - sometimes the equation is also just wrong.

Having a platform to ask these questions would be a valuable aid to research, because it could save a lot of time (the idea of course being that I invest some time to explain details in a paper that I understood easily, saving the asker hours or days of searching, while some other times, I am the one asking). In principle, they are also a good fit for Q&A and they should have a decent QA product. If we had arXiv-feedback, this could actually help other readers of the paper and enhance overall research.

However, we don't want to explain simple equivalence transformations in middle school textbooks, where the person was just too lazy to think about it for five minutes. And we don't want to do calculations in research papers that were left out, because they are tedious but foundational to the field and can be looked up in text books asking person is just too lazy to do them him/herself.

How to distinguish these two? If we want to have more people here who are doing research, it might be a good idea to allow paper questions and disallow all others (this would at least get rid of ambiguities). This is somewhat in line with the idea (Generalizing the homework policy)

Questions which attempt to outsource tedious calculations to the community, without any broader context, are off-topic.

but tries to be a bit more inclusive for research-level questions and a bit more exclusive to avoid ambiguities.

--> One suggestion (needs work): Close non-paper related questions, which want to do outsource calculations with a specific "tedious calculation" close-reason.

Answer 5

The Problem as I see it

The impression I get is that the site is being flooded by a rising tide of poor quality questions which show little or no effort and often lack even a basic understanding of physics. I am not being elitist, I simply deplore lazy questions from those who are obviously not even students of anything, especially not physics.

Since reaching 3k rep, I spend more than half of my time on the site reviewing questions. Currently I vote to close around 7/10 in the "new unanswered questions" queue and a higher proportion in the "Close Votes" queue. This counts questions which I do not feel competent to judge, which I do not touch. Recently I am regularly running out of close votes within 2 hours of getting them, and have to make do with down-voting and commenting instead.

My expectation is that if this trend continues then in the near future the pool of active reviewers will not have enough votes or time to keep up, with the result that the average standard of questions will fall.

Closing questions is frequently pointless. By the time the crucial 5th vote has been cast, answers have often been posted so the question does not get deleted. A few new users respond by posting the same question again. Closure prevents good answers from being posted to bad questions.

Voting-to-close questions provokes resentment and animosity, not only from those posting questions but also other users. Explaining to the OP and others why I have VTC also takes up time - although this is not necessary.

Current policy is inconsistent. We routinely demand that "homework-like" questions must "show effort to work through the problem," yet we tolerate conceptual questions which show little or no effort and are ill-motivated ("I read somewhere... Is this true?" "While I was in the bath I had a thought..." "I was just wondering..."). The site is advertised as being "for students, researchers and academics of physics and astronomy" but we allow anyone, even those with no physics background whatsoever, to post any question. We cannot expect high standards if we adopt inconsistent policies.

Whatever policy is formulated, the most difficult part is implementing it - getting users (especially new ones) to read it, agree to it and follow it. Unless there is a requirement for users to do so, many will not bother. They come here to ask and answer questions, not to study and enforce site policies. It was only after I reached reviewer status that I accepted the closure criteria.

An Even More Radical Solution

I repeat my suggestions given in my answer to Generalizing the homework policy.

I see only two consistent options : either (1) abandon any attempt to control the posting or answering of questions, or (2) place questions 'on hold' as soon as they are posted, and do not open them until they have been approved by reviewers who understand and agree with site policy, rather than those who have their own interpretations of it.

I appreciate that both options are highly unpopular, but at least they are workable, efficient and self-consistent.

1. Abandoning Control

The only reason for closing questions should be that they are off topic, which should mean that they cannot be answered using mainstream physics. It should be open to any user to decide for him/herself whether or not a question meets his personal standards regarding quality or usefulness or research effort or clarity or broadness etc, and to answer or up/down-vote or comment accordingly. Lack of effort and usefulness are already addressed in the up/down-voting feature, so these should not be reasons for closing a question.

This is my preferred option.

Rationale :

Most users simply want to ask or answer questions. Those who ask usually want a quick response. Few use the site for research. Pre-occupation with question quality is inconsistent with allowing unrestricted posting of questions. Minimising reasons for closure will reduce the growing burden on reviewers, and avoid many bad experiences on both sides.

It is patronising of us to decide that some questions should not be answered, and to prevent users who have no objections to the question from doing so.

Abandoning control will allow more poor-quality questions onto the site, but there are plenty of those already which have been closed but not deleted. Voting already identifies good (and/or interesting) questions. If necessary, a periodic purge could remove questions with many down-votes, perhaps via a review queue.

2. Voting To Open (VTO) New Questions

This turns the VTC decision on its head by proposing that all new questions (or perhaps only those from new users with less than say 300 rep, or those with a poor history of closed questions) should be put on hold until approved by reviewers. Criteria for what is on topic would still have to be re-formulated (see below) : the purpose of this proposal is to ensure that policy is implemented effectively.

Rationale :

It is far more effective to get rid of poor questions, and deter poor question-setters, before they have gotten an answer rather than after. Those who need quick answers to trivial questions ("Is this right?" "Where have I gone wrong?" "What am I missing?") will turn away in frustration if it takes 24-48 hours before the question is approved. We would also need to be stricter about "answering in comments" - perhaps by increasing the rep required to comment and flagging such comments for immediate deletion.

It is currently impossible to prevent users from answering questions which are under review, making subsequent closure pointless. For the same reason VTO retains the option of migrating the question instead of closing it.

VTO is consistent with the avowed purpose of the site. Students, researchers and academics will have spent considerable time and effort already working on the problem, and are unlikely to expect immediate answers. Good quality answers to good quality questions often require further research or mathematical analysis, which cannot often be delivered within 24 hours.

It is also consistent with the policy of avoiding duplicates, because there is more time to identify duplicates before answers are posted to the new question.

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Reformulation of Closure Policy

I agree with ACM and heather that the "homework-and-exercises" tag should be removed and the related policy scrapped. All questions should be subject to the same criteria, whatever those may be.

As stated above, my view is that the only reason for closing a question should be that it is off topic, meaning that it cannot be addressed by applying mainstream physics concepts and principles. The question itself need not be mainstream physics, since good science tolerates the unorthodox. I say addressable because for some questions it may not be possible to give an authoritative answer.

There is a lot of subjectivity in the other criteria, which I think are not worthwhile :

Duplicates : It is very difficult to avoid them, and checking is tedious. Even where they are identified before new answers are posted, existing answers may be unsatisfactory, or there may be a subtle difference. Reviving an old question is not easy for a new user (see Re-asking a Duplicate Question).

Unclear what you're asking : Easily dealt with by asking questions to identify exactly what the problem is. This is what comments are for. Very subjective anyway. It is rather contradictory for a question to be closed for this reason when an answer has been posted - and possibly accepted.

Too broad : Easily narrowed down through comments.

Primarily opinion-based : Many such questions (eg resource recommendations, career advice) would be off topic under the above definition (not addressable by applying mainstream physics).

Homework-like : No justification for discriminating based on style of question rather than its content. Questions asking how to apply physics are as much a part of physics as those asking for explanation of a concept or phenomenon - especially for students.

Mainstream physics : Questions about unorthodox physics (eg cold fusion, time travel, perpetual motion machines, warp drive, etc) are addressable using mainstream physics, so they are on topic.

Engineering : "The application of scientific knowledge to construct a solution to solve a specific problem" is what we do all the time as students and experimenters.

Insufficient Research Effort : Too subjective, difficult to judge, and already addressed by down-voting. The reason quickly becomes pointless when somebody provides an answer or even just points out a duplicate or makes a suggestion. If the OP's laziness disgusts you, ignore the question!

Answer 6

There are very few good reason to close questions at all. Even ones that are borderline off-topic. What should be closed is basically just spam, outright crankery, flames, etc. The rest can be dealt with through the normal upvote/downvote mechanism.