Scenario:
Victoria, a coxen for MIT varsity 8 is taking her boat on a practice 2k before the race this weekend. This is a dry run for the race so she wants to record the data and act exactly as she will this weekend. She opens iCoxBox and sets up a new race. She toggles voice recording on so she can hear her voice, and names the new race "Practice 2k, March 2nd." She adds a few notes of encouraging phrases she wants to say during the race, such as "Let's take 10 strokes for MIT!" and "Come on girls, let's take a seat on Harvard!" (her rowers think these would help them during a race and she doesn't want to forget to say them). Her coach wants her to focus especially hard on keeping the stroke rate above 34 and ignore the splits for now (but she still wants the data recorded for review later).
Now that she is all set up, she puts her iPhone into it's place on the boat and tells her rowers to get ready. She starts the race in iCoxBox and tells her rowers to start. During the race, she keeps an eye on all the data and her notes, but her hands are busy steering so she can't modify the interface at all.
After they cross the finish line, she stops the race and saves it. The boat goes back to land and Victoria talks to Coach Jeff about the piece. They pull up the data and run through it in real time, listening to what Victoria says and taking note on how it affects the different numbers (split, stroke rate, accelerometer readings, etc). They decide that she should say "Let's take 10 strokes for MIT!" more often, especially near the middle third of the race, which is where the acceleration readings on the boat were lowest. Victoria sends the data to Jeff so that he can review it in more depth tomorrow morning on his copy of iCoxBox or on a computer.
Design 1: 
screen 1:
learnability: all affordances on the screen
efficiency: tapping is quick and easy
visibility: login state is visible on button and below, number of saved races/trails you have is visible
Err: nothing is irreversible
screen 2:
learn: affordances for dragging, deleting
eff: all things on screen, no dropdowns, quick and easy modifications
vis: all initial data bars are visible, and this is the look of the screen for when you start a race. bad things: ghost trail is hidden unless you are changing it. can't change audio from here (it's in settings)
err: nothing gets deleted, and movements can always be reversed
screen 3:
learn: choosing ghost trail shows in map.
eff: scrolling through list could be tedious with lots
vis: check mark next to chosen trail and previous
err: can come back in and rechoose if necessary
screen 4:
learn: only two buttons, everything else is static
eff: you shouldn't be editing anything,
vis: any data not on the first screen is hidden unless you scroll, which most likely wont be done in a race
err: shouldnt be interacting unless you want to end a race, but race ending is final.
screen 5:
learn: modal interface shows that you can only edit race name
eff: if you want to just use the default and go on, you still need to use this view
vis: previously entered race name is shown to user
err: can always change name later
screen 6:
learn: affordances for places you can view mroe information
eff:
vis: all data for the race visible on one screen
err: only editing feature here is changing the title, which is reversible.
screen 7:
learn: HUD displays playback controls, screen is a copy of the data view while racing which is easy to learn
eff: no way to view graphs of data while realtime playback is occurring, so you might need to go back and forth
vis: controls always overlay screen, which allows you to see controls but they could block some data until you scroll down.
err: you can scrub to any place, so errors are reversible
screen 8:
learn: only a few controls, each labelled appropriately. shows size of data
eff: all on one screen
vis: checkmark by what you are including. size of file changes to report those changes
err: can readd things you remove, once you hit send you can cancel the sending of the file. you can always restart this dialog from the review races screen
Design 2:
Design 3:
Home Screen (#1):
L: simple interface with text dialog, and tab-bars at bottom (familiar UI element to iOS users)
Ef: Basically redundant buttons in familiar tab-bar and within window itself. Multiple ways to accomplish same task.
V: Not much information to convey, and state of application is shown with highlighted tab on the bottom
Er: No errors can occur on this screen. Simple login box can be erased at any time, and tab-bar lets users navigate backwards at any time
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Pre-Race Config (#2):
L: Familiar on/off switches used in iOS on other apps. Buttons and control are all at the bottom (a little non-standard, but there are no other options)
Ef: Remembers previous settings, but having to toggle each option on or off is a little slow
V: Whether all items are selected or not is very clear, but where they are spaced on the next pane is not clear. User might want more control over placement of individual boxes.
Er: User can easily undo any selection made
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Choose Ghost Trail Page (#2.5):
L: Features choosers similar to iOS, and has a cancel/confirm button, so new users wont be afraid that their selections will change something permanently
Ef: If many races exist, scrolling through the chooser could be tedious
V: Has a map representing the ghost path, but more information might be helpful to select the right race
Er: Has a cancel/confirm button pane, so any choice the user makes will be reversible.
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During Race Page (#3):
L: All columns are aligned with the title of the data type displayed to the left of the value. No options to change on this page
Ef: In the previous page, the user has selected the data elements they want to display. If these are not aligned how they desired, they may have to scroll back-and-forth between pages to correct this
V: All data selected is visible and an indicator for whether or not audio recording is enabled.
Er: Errors in arrangement of data can not be easily corrected. The user must navigate to a previous page to change these options
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Select a Race to Replay Page (#4):
L: This page is essentially identical to the "Chose Ghost Page" but with a different title and with a different tab-bar icon highlighted.
Ef: Again, many races may clutter chooser.
V: User may get confused due to subtle difference between "Ghost" and this page, but selecting the same confirm button will do the task the user wanted to do when he or she encountered this page
Er: Very easy to reverse selections with cancel/confirm and simply by returning to this page to select again
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Replay Race Page (#5):
L: This page is nearly identical to the "During Race Page" again with the necessary labels to help the user know what page he or she is on
Ef: Features a play/pause, fast-forward, rewind button. This could be slow if the race is long and the rewind/fast-forward speed is too slow.
V: Displays title of race being played back and the playback tab-bar element is highlighted, not any other, so hopefully the user can tell he or she is not in a real-time race. Also, all data will be displayed, regardless of data layout when the piece was recorded
Er: Play/pause allows the user to replay sections or jump, so few errors that are uncorrectable can occur.