How worried should I be about action consistency across multiple pages?

Question

I'm working on part of a redesign for a big, enterprise web application. This part has the user managing a bunch of settings that govern how the rest of the application is used.

These screens follow a similar pattern - They start with a table with anywhere from 1 to 30 rows, each row containing a name and description. Clicking the row takes the user to another page that contains actual editable fields. Depending on the screen, sometimes these are extremely simple, maybe just two or three fields on it. Other screens are more complex, with tabs and fields and controls all over the place.

^{download bmml source – Wireframes created with Balsamiq Mockups}

It's difficult to come up with a good example, but here's a shot: imagine if you had a system that catalogued car parts. You've got a table for each type - so a table for tires, a table for spark plugs, a table for fenders, and so on. Each of these items has a variable level of complexity - maybe for spark plugs, all you need is the model number. But for engines, there are all kinds of fields, and lots of complex values to enter.

My problem: so the particular problem that I'm trying to solve here, is that there are a lot of pages with very little information on it. In total, there are probably about 40 different tables (each on different pages). Probably 30 of those are "simple" - so for each row in the table, there are less than 5 associated editable fields. For those, it would be much easier to edit the fields in a lightbox/dialog rather than going to a whole different page.

For the other 10 tables, those have "complex" editable fields. Of course, they vary, but the point is it doesn't make sense to put them in a dialog. They really need their own page.

(finally!) My question: So I've got 40 pages, each with a table on it that looks basically the same. Currently, when you click on a row, it always goes to another page. If I change it such that sometimes it opens in a dialog, and sometimes it opens a new page, how confusing is that going to be?

Would it be advantageous to have some kind of indicator, or slightly different set of controls for pages that open a lightbox vs another page? Suggestions/examples of what that might be?

Answer 1

Consistency is a key element to avoid mistakes, give security, improve the system and fix errors.

As you notice I mentioned two non related aspects, user experience and system.

Consistency is going to give the users of the application a sense of security since they know "what is going to happen", they know how the system is going to react and they feel at ease because it is how it "should be". Of course, if somebody uses the system long enough, whichever way you choose is going to be perceived as the normal one, but it's better to have the feeling for the whole system than for each page.

For the system side, if you have similar mechanics being accessed on different interfaces, means that you have at least two places to touch if you have to fix or improve something. Worst if somebody else has to do it.

Considering what you mention, you already have the system working in the right way.You may be interested on some reading about the subject like Consistency: Key to a Better User Experience, or Why Consistency is Critical, or 10 Usability Heuristics for User Interface Design where One of the elements mentioned by Nielsen is consistency, he even has a book just for that subject. Those links are not very recent, but they reflect a situation that doesn't change much.

If there is any real advantage on changing things, then do it, otherwise, keep it consistent.