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Do Zebra Stripes Actually Help?
RyoShin writes "A List Apart, an excellent resource for web development and related aesthetics, has put together an article based on original research by Jessica Enders into 'zebra striping.' From the article: 'Zebra striping [coloring alternate rows] is used when data is presented in an essentially tabular form. The user of that table will be looking for one or more data points. Their aim is to get the right points and get them as quickly as possible. Therefore, if we set a task that uses a table, and zebra striping does make things easier, then we would expect to see improvements in two things: accuracy and speed.' The conclusion of the peer reviewed paper? It's a wash. Striped tables offered only a slight increase in accuracy and speed overall. The article notes a few other benefits to using Zebra striping, so it's all up to the individual."
Yes, much in the same way that Go Faster Stripes work...
Summation 2
Finding data in nine columns with alternating text and numbers is easy. Try upping the number of columns, using only numbers, use close spacing, and reduce the text size. Then you will see a difference. This experiment is flawed because they didn't test how the values scale with more columns and less helpful clues (like the differences between text and spacing in their sample table). This article should have been rejected for not taking into account these issues.
I don't have a study to prove it, but coloring or otherwise marking every Nth row, where n is a smallish number, say 2-5, helps.
Anyone else remember fanfold wide-format computer paper that was colored white and green in alternating blocks of 3 rows each?
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If your are PRINTING a checklist for use outdoors, at night, etc striped tables IMO work MUCH better for checklists. In the Air Force we used them for generation checklists (scan down task lists at the side vs tail
numbers at the top) to fill in times.
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It depends on the program displaying the data. Some programs allow you to to click on the row and get that one row highlighted. That is a huge help. Others like tables on a web page don't allow that. In that case I say it does help.
Also the size of the table makes a difference.
See my blog http://ilovecookes.blogspot.com/ for light hearted technical information.
is irrelevant.
On narrow tables they don't make a difference. But on wide tables they're almost a necessity. Without any table cell borders, like a spreadsheet, or striping, the eye easily wanders up or down into another row when reading across. I can say anecdotally that I'm far more accurate and faster when reading a table with stripes.
Either way, they certainly can't hurt, especially if they're a pale color. So why are we even having this discussion?
Developers: We can use your help.
So they conclude it doesn't help (though their own data says that it does, even though it's slight) based on THAT table? Maybe they should try it again with a zebra striped table where the difference between the colors used is slightly more pronounced. I don't know about the rest here but I personally think I had a harder time with that because the color difference between rows was so slight than if they had left out the color. Played tricks on my eyes.
If zebra striping doesn't actually make it easier to identify which cells actually belong to a given row - maybe a rethink of what is trying to be accomplished here could help. Perhaps highlighting of the row under the cursor?
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Personally, I think that they are done best when striped in sets of three, makes following the line even easier. But that's not my point. Apparently the article says that it offers only minor improvements in accuracy and speed. That's not a wash, that's a minor improvement. Considering the virtually no effort to achieve the minor improvement, I'd call that a significant benefit.
Still, a slight improvement is still an improvement.
Isn't an improvement in accuracy is better than no improvement, or a decrease?
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I can tell you why it didn't help. They formatted their table with large spaces between columns and they had only 9 rows. If they tried the same study where they also varied the number of rows I am sure they would find that as the rows increase the positive effect of zebra striping increases. It seems they had a bias built into their test in order to find something unexpected... otherwise the study would have proved pointless.
I can see the Slashdot headline now, "A practice used for over half a century still proves to be useful!" Somehow, I think such a headline falls under the category of "not news."
Exactly. Is the improvement in "accuracy and efficency" really the only goal? What about a more pleasurable user experience, reduced stress or sense of fatigue, etc? Essentially, any time we treat humans like machines we miss a huge part of the equation. If a humans overall comfort level is increased, as long as it is not in a way which directly detracts from the work they are performing (alcohol comes to mind), they're almost guarunteed to be more productive and committed in the long term. This is the same reason we buy fancy coffee for drastically overmarked prices, instead of the dollar cup from BlowJoe Coffee. Aesthetic and experience matter, and if there are no marked *decreases* in efficiency due to table striping, then I'll do it every day of the week.
I see a problem with the experiment. The hard part of the questions involves scanning down a column , where horizontal striping obviously does not help.
Nystagmus is a condition where your eyes oscillate at a frequency of about 1 Hz (roughly), usually horizontally. Having rows and especially columns coloured differently helps very much for someone affected by Nystagmus, to distinguish between columns.
BTW, a wider font like Verdana is also highly recommended.
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I'll get the wtf out of the way first
"Given that applying zebra striping in an electronic medium is a nontrivial task"
Say what? Any application that is based on columns and/or rows has trivial access to those columns/rows as separate entities. Markup for such columns/rows is easily changed. 'mod N 2 == 0? grey:white' is hardly nontrivial, it's so basic that if you can't manage to do it, you must be using the wrong software.
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Now for the scope - it seems like the only research they have done is when data in the sheet is dense and the sheet itself is not all that wide.
Now try with a wide sheet and instead of every 'cell' or at least one of its close neighbors having data in it, imagine lots of empty cells. Now try and see if zebrastriping helps or not. I can guarantee you that without any visual cues, your lining up of something in the leftmost column to the same line on the rightmost column is going to fail far more often than you'd like.
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Oh wait, they even admit as much:
"However, there is clearly a need for additional studies to investigate how task difficulty and the size of the table/form influence the effect of zebra striping."
No shit. I'm glad you admitted that your sample size is too low.
They also help the pack slice their dinner up fairly. For very lazy lions there are now even zebras with perforated easy-claw edges down every third black stripe.
The difference is small for a half-assed 9 column table with lots of visual clues like they prepared. Try a real table in small print without alternating text entries and with narrow spacing. The difference will be enormous.
On printed pages, I've seen people using a ruler to help scan through tables of numbers. I thought that was where the idea for zebra striping came from. Honestly, I'm surprised that it was only a minor improvement. Maybe it's just me and my bad eyes, but I think it helps tremendously. It probably also matters how many columns there are -- the more there are, the more it helps. I'd also suspect that fatigue would kick in, so it would make less difference for, say, less than 100 exercises, and more difference after that. [Didn't RTFA. Maybe they address those points.]
I'm no GUI designer, but when I make utility web pages that use tables, I tend to use either zebra striping or a tr:hover that uses a light yellow to highlight the line under the mouse pointer. That way, if I feel I need the help to track through the table, I just run the mouse down the columns and it lines up the current row for me very nicely. IMHO, this is a nice compromise where zebra striping might not look good, but the user might want the help nonetheless.
Perhaps I'm being a bit pedantic, but am I the only one that thought some of the questions were oddly worded?
Here's what I view as correct answers:
Q What is the name of the screw that costs $35.66?
A: None. The M28 screw costs $35.66 per 50.
Q There are 664 screws of which minor diameter tolerance?
A: None. The M18 Screw has a minor diameter tolerance of 8g, and there are 664 of those, but there are 1442 screws with a tolerance of 8g.
Q: There are 292 screws of what thread pitch?
A: None. There are 292 M16 screws which have a thread pitch of 2mm, but there are 527 screws with a thread pitch of 2mm.
two things. first, it's only insignificant if it took effort to do. if it's free to do, and it doesn't hurt, and it rarely helps, then it's worth doing.
second, authetically pleasing is also worth points when it doesn't hurt anything else.
third, and perhaps most importantly, just because I can drive as fast and as safely on a sunny day as I can on an over-cast day, doesn't mean that one isn't easier than the other. professional typers type just as quickly on a qwerty keyboard as they do on a dvorak keyboard because they are professional typers and will adapt to just about anything. But they still expend more effort on a owerty keyboard than on a dvorak one -- simply put, their fingers travel farther.
I don't suppose that this experiment studied the cognitive effort required, nor stressed the patricipants to measure their accuracy during significant distraction -- like driving, or listening to something important, or carrying a conversation, or giving a presentation.
It seems that way, doesn't it?
Zebra striping becomes more useful the further apart the key row is from the data in the row. It also becomes more important if there are no lines between the rows and columns. It's practically essential when you're trying to view a wide table where the key must be scrolled off screen to view the pertinent data.
In this study, the key row was the tolerance in grams, and the data was the factory outlet boolean. They were an inch and a half apart from each other, and there was no necessity to interpret multiple values in a row, but only vertically scan the key column and test for the existence of a row that has yes in the factory outlet column right next to it.
These people are spreading misinformation. The study was so contrived to support the premise, and so consciously avoidant of the actual situations where zebra striping becomes useful, that it's difficult to believe it wasn't intentionally done. If nothing else, there was far, far too little study done to make any conclusion whatsoever.
Whoever is behind article this should be working at MacDonalds.
-1 Uncomfortable Truth
Apart from the just plain wrong statistical reasoning, the experiment was done under uncontrolled conditions over the Internet. The sample table in the article actually had lines separating the columns and rows. Geez, with that, it's not surprising that the author finds no differences!
Zebra striping may or may not help significantly, but this paper won't tell you either way.