Lately I've come across a lot of resume, portfolio or business websites showing the level of proficiency in a certain array of skills by using percentages.
For example, I saw something like this on the website of a small company involved in web design:
This confuses me. Does this mean you master something when you reach 100%? Is it possible to have 0% in a skill? How much XP do you need to gain 1 more percent?
The percentage scale makes sense if the company administers a pre-interview technical test and these are pass marks.
Otherwise the percentages don't make sense. After all a percentage only makes sense in reference to something else.
What would make more sense is:
If you are applying to a job advert with this information, I would try to address your competencies on each of these areas citing your experience, qualifications and (most importantly) what benefits you can provide to an employer.
Why describe the level of proficiency in a skill by using percentages?
This allows for lazy decision making by people doing initial screening. Remember that numbers are magical to some people so they believe that PHP=40% is better than PHP=30% even if those numbers are arbitrarily self assigned.
I agree, percentages like this are useless. Without some set standard of what 100% is me saying 78.8% is just a arbitrary number.
As to what you can do about it? If you need to rank your own skills, ask first what they think 100% is, and when someone gives you a percentage, ask them what 100% means to them.
These are just numeric representations of vague statements. Using the sample values:
Could mean:
All of this is basic conjecture. As you can tell by glancing at the other answers, there is no real formal process for precisely calculating the numbers. So what this means is that we must take these numbers as rough estimates, and possibly guesses. * I have been known to spend roughly 80% of a standard-length work day in HTML, but only 30% of my career was doing PHP-related stuff.
We don't know, just based off of the numbers, what 100% means. It may mean any one of these things:
I can think of multiple reasons why a person uses numbers instead of clear sentences that have more meaning. One is that percentages may be much faster to read, which may be a benefit.
On the other hand, rather than trying to respect the time of a hiring staff, the person might be intentionally being a bit vague, so that specific and verifiable claims don't go on record in a way that could be the basis of taking formal/legal action against them (such as terminating employment on the basis of provably false statements on the resume).
Another possibility is that percentages may show some relative strengths, just trying to show HTML is better than PHP. (In fact, with many people these days, they might even be forgetting that 80% means four fifths of something, and might just be giving themselves scores using numbers that they see more frequently, like progress in a video game.)
Ultimately, this is failing to communicate with some people. One of the key principles of successful communication is that the message must be successfully understood, not just transmitted/delivered. Proof that this method is failing can be seen by looking at the chorus of other answers to this question. So far, they aren't offering anything more specific either. However, the author may not be realizing how much struggle people have with interpreting whatever they are intending to communicate.
So, don't do what they did. Don't provide meaningless numbers (without any other details that provide sufficient context to understand them).
.html" as well as files that end with ".htm" so there is actually a widespread difference in whether people prefer that L.
As you already pointed out, obviously this kind of presentation is somewhat relative and therefor meaningless to directly compare job applicants.
In my opinion, the only usefull information which you can transport by categorizing your skills into percentages, is the relative weighting which you give to the particular skill in comparison to the other skills listed.
90% PHP
30% CSS
Would therefor have the meaning, that you have a strong focus on PHP development. It wouldn't necessarily mean you are an PHP expert.
As you said that you saw this a lot on portfolio or business websites, I must point out that a lot of sites display this info in excactly that way, because many stock themes feature such a presentation (here is a typical example). A lot of small companies use stock themes to build their website nowadays, because it's cheap and fast.
Such websites are build design first and content last - which means that in the majority of the cases, there hasn't been put much thought into the relevance of the information for the visitor itself (it only has to look good ...).
I would only take it as a hint, showing the technological emphasis of that company.
I have personally never seen it in a resume and also wouldn't advise you to use this in a resume.
I recently had this in an interview where I was asked to rate my knowledge and/or proficiency in a variety of things and after which I then gave my explanation for why I chose that particular rating. Afterwards when I was given some feedback about it, they mentioned that in one of the questions I answered with a low rating and gave my explanation why I chose it and another candidate gave themselves a near perfect rating using the exact same explanation I gave for my poor rating!
In essence it seemed like they were using it as a method not only to gauge how experienced the candidate was (through further prompting) but to gauge how accurate the candidate's perception was of their own abilities. I think when it's used in this context it can be quite beneficial, but as others here have mentioned if a rating of any kind is used without some time of criteria to compare it to - it's useless due to its subjectivity - As my example above clearly illustrates - another candidate and I both described ourselves as having the same skills in a certain area - but one came off with a very high view of their ability, and the other didn't.
I am going to propose a possibility drastically different from every other previous answer.
If you say you see a lot of these crop up, there is a chance that they are a result of some sort of automated (probably online) test/quiz.
The ratings definitely match up to what they would be if it was an online quiz, many of which like to use percentage results.
Now, if that's the case, you can be the judge of just how accurate an online quiz is at assessing proficiency. I'd assume not very good, without proof to the contrary.
The numbers are intended to give the candidate's self-assessment of various areas of expertise. They're to give a starting point for the conversation.
I've been asked by technical recruiters to rate my various skills in a range from 1 to 10. How is your level of X expertise? I haven't coded in X in years, am not interested in X and am not advertising my skills in X. Answer: 2 of 10.
How about language Y? I've been coding in language Y for 5+ years. I've been involved in the SO community for that language for 4 years. I am fairly confident in my ability, but I'm not John Skeet. 8 of 10.
As an interviewer, you use those numbers no differently that any other information available on the resume. You need a DBA and they rate themselves as a 1 of 10. Are they willing to learn and you willing to train? You may have a match. They rate themselves a 9 of 10 and you're looking for a 1? Maybe look at someone else.
Don't think those numbers are reliable? Great! You're a smart interviewer. Your job is to test the candidate and see if they're right for the role. Those percentages are no more or less misleading, unhelpful or dishonest than anything else listed on any resume. Caveat Emptor.
