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Alice, Bob, and Carol haven’t seen each other for a while, and decided decide that they should meet up tonight and have dinner together. None of them had have any concrete suggestions for a restaurant, and since all three friends are rather indecisive, so they decided decide to meet at 77 Mass Ave and then decide where to go. Alice would prefer prefers to go somewhere nearby, but is otherwise indifferent, whereas Bob would prefer prefers to go across the river. Carol doesn’t care where they go, but she’s strongly in the mood for Chinese food , and would prefer prefers that it’s not too expensive (but not too cheap either). Alice, Bob, and Carol need to agree on a specific restaurant that they can all be reasonably happy with. Also, they would prefer to come to an agreement sooner than later, given that they’re standing around outside at the moment, and have some means for narrowing down their options and getting specific suggestions.

Alice, given that she feels strongly about location, suggests going to Central Square, and Bob suggests going to the Back Bay. Carol mentions that she really wants Chinese food tonight, and would prefer that it be moderately priced. Given that information, someone points out that the Prudential Center P. F. Chang’s fits several of their criteria (Back Bay, moderately priced, Chinese food). Even though it doesn’t fit all of their preferences (which it can’t, because Alice and Bob have mutually incompatible preferences for location), it does reasonably accommodate most of them, so the three friends agree that it’s a good choice.

Designs

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Design

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Learnability

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Efficiency

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Safety

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Spin the Wheel

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• Follows roulette metaphor for gambling
• Spinning wheel simulates random decision making process, but slices are unequally sized, suggesting weighted probability distribution
• Pile of coins provides affordability to move them onto desired slice on choice wheel (although drag and drop feature may not be evident at first glance)
• Handle on side of wheel provides affordability for spinning (label on the side makes this easily visible)
• Not obvious there are multiple stages in bidding process (location, price, cuisine), so 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
  Medium

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• Lots of widgets to manipulate, so requires more user interaction and time (dragging coins to desired section on wheel, pressing buttons to move back and forth between rounds, spinning the wheel to make decisions)
• Lots of rounds (3 rounds of betting on each criteria, 3 runs for deciding on each criteria, 1 round of betting on final restaurant, 1 run for deciding on final restaurant)
• Lots of turns (each player is passed the phone twice + group rounds)
  Medium

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• Doesn't allow users to type bet amount, and system disables coin dragging when total coins = 0. Therefore, it is impossible to bet more coins than are in the bank. 
• Users can move coins into and out from choice slice on wheel if they change their mind. choices aren’t committed until "next person" arrow button is pressed. 
• Next and Previous arrow buttons allow user to navigate between screens in betting stages (especially important for first time users since they will most likely no know there are multiple criteria to bid on)
  Medium

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Auction Sale

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• Intuitive interface - most people familiar with auction sale metaphor
• Only one button to press ("Bid" button)
• Since it's impossible to go back and forth between criteria rounds, may take first-time user a couple of trial and error attempts to figure out how to use the interface properly
  Medium

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• Each each individual has to wait for everyone else to finish bidding (can't skip round even if individual doesn't care about the choice made)
• Lots of screen transitions (2-3 for each of the 4 criteria rounds)
• Not many widgets on each screen (1-2 max) -> easy to manipulate
  Medium

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• Can't retract a bid.
• Can't change a criteria. Once the bidding is over for a criteria, it's final.
  Low

. To do this, they need a way to narrow down their options and make a decision based on that.

The three friends decide to use the DecideIt app to help them figure out where to go. Bob pulls out his smartphone and opens the app. First, the app allows them to input whatever suggestions or preferences they already have, or the app can also make a few suggestions for them. Since Bob wants to get out of Cambridge for a change, he adds Back Bay to the list of location choices. Alice prefers to stay close by, so she takes the phone and adds Central and Kendall to the list. Carol doesn’t care where they go. She just wants Chinese food and something that is not too expensive, so she adds Chinese to the cuisine choices list. The group also picks some other choices from a stock list of location, price, and cuisine options. Throughout this selection process, Bob's phone is constantly passed around the group, so no one is standing idly on the side for long.

Next, it’s time for each person to express their own preferences. DecideIt provides an interactive UI, which allows users to express their preferences by betting (Spin the Wheel and Slot Machine) or bidding (Auction Sale) on the choices they selected in the first stage. During this stage, the phone is passed around the group so each person can do their betting (or bidding). At each turn, a player bets (or bids) on their desired preference for each of 3 criteria: location, price, and cuisine. Each person should take no longer than 1 minute (depending on the design). For Spin the Wheel and Slot Machine, the phone is frequently changing hands, reducing awkward downtime for the group. Auction Sale is played individually on each person's phone, but they are constantly interacting through the interface, so no one is bored for too long.

Finally, the app makes a decision on the criteria, based on people’s bets (or bids), and offers suggestions of restaurants that satisfy that criteria. Group members choose from the selected restaurants, and voila, the decision is made!

DecideIt makes the decision-making process more engaging and fun. It specifically targets groups that are very indecisive and do not have many ideas about where to go. By making the process a strategic game, DecideIt encourages people to participate in the decision-making process and offer their own opinions. It also introduces randomness in the decision process, so groups that are tired of always going to the same place can explore new, unvisited venues. For groups that are dominated by strong personalities, DecideIt spreads out control amongst group by forcing players to place their highest bets (or bids) on only what is most important to them. That way, it is more likely that everyone gets a say.

Designs

All designs model the decision-making processing through an interactive game which involves an element of randomness. Spin the Wheel and Slot Machine allows players to place strategic bets on their preferences, whereas Auction Sale allows players to engage in competitive bidding to reach a final restaurant decision. Each design differs in their degrees of user interaction, group collaboration, and completion time. To learn more about how each interface works, please peruse the detailed descriptions below along with their corresponding figures

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Slot Machine

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• Uses standard mobile phone widgets (spinners, buttons, labels), so interface is intuitive and straightforward
• Only one person is using app at a time, so people can teach others how to use the interface
• Not obvious that selection is based on weighted probability distribution
• Obvious that there are multiple criteria to bid on, since all of them are presented on one screen (instead of separated, like other two designs)

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• All of the criteria (location, cuisine, price) are chosen on one screen (as opposed to separate screens in other two designs)
• Spinner used for selecting criteria and points (faster to manipulate than dragging coins to special sections on spinning wheel in "Spin the Wheel" design)
• Players have to take time to do some mental math to figure out point assignments so they total to 100 (the max).

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Design 1: Spin the Wheel

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The app generates 3 choices for the group to vote on based on the final criteria decisions made in step 3 (Figure 7). Figure 7 allows users to find out more details about each restaurant choice. The "Round 2" button takes the game into the final round, where individuals must vote on their desired restaurant choice (Figure 8). The final restaurant choice is determined by the slot machine based on the weighted probability scheme mentioned in Stage 3 and in Spin the Wheel (Figure 9).

Design Analysis

Spin the Wheel

Learnability

Pros

• 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.

Efficiency

Cons

• Lots of widgets to manipulate
  • Requires more user interaction and time (dragging coins to desired section on wheel, pressing buttons to move back and forth between rounds, spinning the wheel to make decisions)
• Lots of rounds
  • 3 rounds of betting on each criteria (individual)
  • 3 spins for deciding on each criteria (group)
  • 1 round of betting on final restaurant (individual)
  • 1 spin for deciding on final restaurant (group)
• Lots of turns
  • each player is passed the phone twice 

Safety

Pros

• App prevents over-betting
  • App doesn't allow users to type bet amount, and system disables coin dragging when total coins = 0. Therefore, it is impossible to bet more coins than are in the bank. 
• Apps allow users to modify bet amounts
  • Users can drag coins into and out from choice slice on wheel if they change their mind. Choices aren’t committed until "next person" arrow button is pressed. 
  • Next and Previous arrow buttons allow user to navigate between screens in betting stages (especially important for first time users since they will most likely no know there are multiple criteria to bid on).

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 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 to manipulate
• 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
  • 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".