Mobile App Back Button Placement

Question

I am building a mobile application that uses a button to launch the navigation menu (much like the Path or Facebook interface). I also want to add a back button. The standard seems to be to place the navigation menu option in the top left hand corner.

My question is, is it ok to place a back button in the top right hand corner? Should I replace the main navigation menu with the back button and only allow access to that menu from the main screen? Should I swap the location of the back button and the navigation menu? Is there a standard for this or does it matter?

UPDATE:

Here's a screenshot of what I currently have:

Answer 1

If this application is to be designed for iOS then placing the button on the right is actually a violation of Apple's Human Interface Guidelines for the Navigation Bar (see the Guidelines section):

A back button should appear to the left of the title, and it should be labeled with the previous level’s title.

If this application is being designed for Android, Windows Phone, and (I believe) BlackBerry a back button is not needed and would be redundant as there is a hardware button on the phone designed for exactly this action. If you're building for WebOS I believe there is a gesture used for back and thus no additional back button is needed.

Placing your back button on the right can cause confusion as users may not consider the shape and content first, but rather the placement and assume it means "next/continue/forward".

Placing the button on the left puts it at the front of left-to-right readers' visual scanning pattern and thus it's easier to find. If you're designing for right-to-left reader's exclusively, then you might be able to justify a right-hand placement, but you'd need to flip your icon around so the arrow points to the right as well.

See also this site for further examples on why placing the back button on the right may be a bad idea.

Answer 2

I believe it matters, but I don't know the answer. However, given these two choices it seems relatively obvious that the back button should be on the left, and the navigation menu next to it:

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

User testing may prove me wrong. Prototype your two designs, but put latin names on the buttons (as in my mockup above), then ask users: what will happen if you tap this button? What will happen if you tap here? You'll quickly find out if your positioning makes sense, and my guess is that users will understand the interface better with the back button on the left.

Answer 3

It does matter as Google and Apple trying to maintain a static user experience about back button concept (Especially android is strict about this concept as they implemented left upper corner as previous button !!!not back!!!, see action bar at Android Design Guideline). Still there is no chain holding you down to put the back button wherever you need, if you believe it should be at there.