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- Intuitive betting interface
- Spinning wheel and presence of coins suggests gambling game.
- Weighted randomness is evident, promoting strategic betting
- Spinning wheel simulates randomness, while unequal sections of choice wheel suggest weighted probability distribution.
- Affordability for manipulating sophisticated widgets
- Pile of coins provides affordability to move them onto desired slice on choice wheel. Instructional arrow improves visibility.
- Handle on side of wheel provides affordability for spinning. Instructional arrow improves visibility.
- People can teach each other
- Since only one person uses the app at a time, other group members can help each other learn the interface faster.
Cons
- Breakdown of tasks not immediately evident
- Not obvious there are multiple stages in bidding process (location, price, cuisine), so a first time user may have to transition back and forth between screens when they realize they don't have enough coins to bet in each criteria round.
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Auction Sale
Learnability
Pros
- Intuitive bidding interface
- Most people are familiar with how an auction sale works
- -- they understand the metaphor already.
- Does not require much user input
- Very few widgets (
- usually just a "Bid" button) on most screens
- . App does most of the work, so there is not as much to learn.
Cons
- Can't back up and redo stages: may
- May take first-time users a few trial-and-error runs to learn the interface and metaphor fully.
Efficiency
Pros
- Few widgets on each screen: easy
- Easy to manipulate
Cons
- Parallelized bidding process
- Everybody is completing the bidding process at the same time, so people don't have
- to wait for others to finish making their choices.
Cons
- Bidding completion time can be long if there is much contention
- Each person has to wait for bidding to finish at each round. One
- person can't skip a round even if he/she doesn't care about that aspect of the decision.
- Lots of screen transitions (3-4 per stage, four stages)
Safety
Cons
- Can't retract a bid
- Can't go back once a round is finished: once a decision is made, it's final
Slot Machine
Learnability
Pros
- Consistency with standard smartphone widgets promotes fast learning
- Only contains standard
- smartphone widgets, which is consistent to other smartphone apps
- , making this design for intuitive and straightforward.
- People can teach each other because
- Since only one person uses
- the app at a time, other group members can help each other learn the interface faster.
- Less need for trial and error testing
- It's obvious that there are different criteria to bid on. Therefore, people know immediately that they have to distribute their point assignments.
Cons
- Weighted probability scheme no evident, purpose of point assignment unclear
- It's not obvious that selection is based on weighted probability distribution. Therefore, people may not understand how to why to assign points to their desired criteria choice.
Efficiency
Pros
- Can bet on all three criteria at once
- The
- betting stage on different criteria are all on one
- screen, instead of 3 separate screens as in "Spin the Wheel" and "Auction Sale".
- Spinning widget faster than coin drag
- The spinner used for selecting location, price, type and points is faster to manipulate than putting coins on the wheel or waiting for others' auction decision.
Cons
- Mental math for point assignment takes time
- Users have to take time to figure out the allocation of points to make sure that they sum up to 100.
Safety
Cons
- Betting stage cannot be undone
- There is only one screen for different criteria (as opposed to going back and forth between screens in "Spin the Wheel")
- . Therefore, if errors are made on one screen due to learnability problems, all criteria are affected. Users can't change choices after pressing "Done".