McInterface

McInterface
User Interface Design & Development Project
SIMS 213, Spring 2001

: Linda Harjono, Saifon Obromsook, John Yiu Chi Wai

Pilot Usability Study

Formal Experiment Design

Hypotheses

1. Allowing users to place orders using an "Order" button next to each food/drink item is clearer to users than providing instruction: "Touch the picture to order the item' and allowing users to place orders by touching the picture of the item.

2. The 'indirect ordering process' better suits users' flow in ordering an item than the 'direct ordering process.'

3. It is more necessary to have ‘Remove’ buttons in Order Summary than quantity changers.

Factors (Independent Variables)

Way of initiating an order:

Level 1: Providing the "Order" button next to the picture of each item in the ordering page ('Order button')
Level 2: Providing instruction: "Touch the picture to order the item" ('Touched picture')

Flow of ordering an item on the Order Summary

Level 1: With a Pop-up "Details" Page Window everytime users place an order ('Indirect')
Level 2: Without a Pop-up "Details" Page Window everytime users place an order ('Direct')

Locations of ‘Remove’ button and Qty changer:

Level 1: With a quantity changer, but without a "Remove" button for each item in Order Summary ('Quantity changer')
Level 2: With a "Remove" button, but without the quantity changer for each item in Order Summary('Remove button')

Response Variables (Dependent Variables)

Time perceived by users to perform the following tasks:
- Place an order.
- Complete a task scenario that requires them to have a special request.
- Cancel an ordered item.
- Change the quantity of an order item.
Time actually taken by users to perform the above tasks.
Level of satisfaction

Blocking

We want to test each level of one factor at a time while blocking/freezing the other two factors. We decided that the factors should be tested between-subject since learning effect can be significant. This might be because our interface is designed to accomodate short and simple tasks, and that our design intention has been that the interface should be usable without any prior learning. Since we have 2 levels for each of the three factors, so we have 8 combinations of possible experiments:

'Order button' - 'Indirect' - 'Quantity changer'
'Order button' - 'Indirect' - 'Remove button'
'Order button' - 'Direct' - 'Quantity changer'
'Order button' - 'Direct' - 'Remove button''
'Touched picture' - 'Indirect' - 'Quantity changer'
'Touched picture' - 'Indirect' - 'Remove button'
'Touched picture' - 'Direct' - 'Quantity changer'
'Touched picture' - 'Direct' - 'Remove button'

We intend to repeat each of these 8 combinations 6 times, which gives a total of 48 repititions. We think that this is realistically a possible number since McDonald's repeat customers give us a large pool of users to recruit from.