The Multiple Errands Test (MET) evaluates the effect of executive function deficits on everyday functioning through a number of real-world tasks (e.g. purchasing specific items, collecting and writing down specific information, arriving at a stated location). Tasks are performed in a hospital or community setting within the constraints of specified rules. The participant is observed performing the test and the number and type of errors (e.g. rule breaks, omissions) are recorded.
The Multiple Errands Test was developed by Shallice and Burgess in 1991. The measure was intended to evaluate a patient’s ability to organize performance of a number of simple unstructured tasks while following several simple rules.
See Alternative Forms sections below for information regarding other versions.
The original Multiple Errands Test (Shallice and Burgess, 1991) was comprised of 8 items: 6 simple tasks (e.g. buy a brown loaf of bread, buy a packet of throat pastilles), 1 task that is time-dependent, and 1 that comprises 4 subtasks (see Description of tasks, below). It should be noted that the MET was originally devised in an experimental context, rather than as a formal assessment.
Description of tasks
The original Multiple Errands Test (Shallice and Burgess, 1991) was comprised of 8 written tasks to be completed in a pedestrian shopping precinct. Tasks and rules are written on a card provided to the participant before arriving at the shopping precinct. Of the 8 tasks, 6 are simple (e.g. buy a brown loaf of bread, buy a packet of throat pastilles), the 7th requires the participant to be at a particular place 15 minutes after starting the test, and the 8th is more demanding as it comprises 4 sets of information that the participant must obtain and write on a postcard:
(a) the name of the shop most likely to have the most expensive item;
(b) the price of a pound of tomatoes;
(c) the name of the coldest place in Britain yesterday; and
(d) the rate of the exchange of the French franc yesterday.
The card also includes instructions and rules, which are repeated to the participant on arrival at the shopping precinct:
“You are to spend as little money as possible (within reason) and take as little time as possible (without rushing excessively). No shop should be entered other than to buy something. Please tell one or other of us when you leave a shop what you have bought. You are not to use anything not bought on the street (other than a watch) to assist you. You may do the tasks in any order.“
The participant is observed performing the test and errors are recorded according to the following categorizations:
Inefficiencies: where a more effective strategy could have been applied
Rule breaks: where a specific rule (either social or explicitly mentioned in the task) is broken
Interpretation failure: where requirements of a particular task are misunderstood
Task failure: where a task is either not carried out or not completed satisfactorily.
Time taken to complete the assessment is recorded and the total number of errors is calculated.
Different versions of the MET were developed for use in specific hospitals (MET – Hospital Version and Baycrest MET), a small shopping plaza (MET – Simplified Version), and a virtual reality environment (Virtual MET). For each of these versions, 12 tasks must be performed (e.g. purchasing specific items and collecting specific information) while following several rules.
MET – Hospital Version (MET-HV) (Knight, Alderman & Burgess, 2002)
The MET-HV was developed for use with a wider range of participants than the original version by adopting more concrete rules and simpler tasks. Clients are provided with an instruction sheet that explicitly directs them to record designated information. Clients must achieve four sets of simple tasks, with a total of 12 separate subtasks:
The client must complete six specific errands (purchase 3 items, use the internal phone, collect an envelope from reception, and send a letter to an external address).
The client must obtain and write down four items of designated information (e.g. the opening time of a shop on Saturday).
The client must meet the assessor outside the hospital reception 20 minutes after the test had begun and state the time.
The client must inform the assessor when he/she finishes the test.
The MET-HV uses 9 rules in order to reduce ambiguity and simplify task demands (Knight et al., 2002). Errors are categorized according to the same definitions as the original MET. The test is preceded by (a) an efficiency question rated using an end-point weighted 10-point Likert scale (“How efficient would you say you were with tasks like shopping, finding out information, and meeting people on time?“); and (b) a familiarity question rated using a 4-point scale (“How well would you say you know the hospital grounds?“). On completion the client answers a question rated using a 10-point scale (“How well do you think you did with the task?“).
MET – Simplified Version (MET-SV) (Alderman, Burgess, Knight & Henman, 2003)
The MET-SV includes four sets of simple tasks analogous to those in the original MET, however the MET-SV incorporates 3 main modifications to the original version:
More concrete rules to enhance task clarity and reduce likelihood of interpretation failures;
Simplification of task demands; and
Space provided on the instruction sheet for the participant to record the information they were required to collect.
The MET-SV has 9 rules that are more explicit than the original MET and are clearly presented on the instruction sheet.
Baycrest MET (BMET) (Dawson, Anderson, Burgess, Cooper, Krpan & Stuss, 2009)
The BMET was developed with an identical structure to the MET-HV, except that some items, information and a meeting place are specific to the testing environment (Baycrest Center, Toronto). The BMET comprises 12 items and 8 rules. The test manual provides explicit instructions including collecting test materials, language to be used in describing the test, and a pretest section to ensure participants understand the tasks. Scoring was standardized to allow for increased usability. The score sheet allows identification of specific task errors or omissions, other inefficiencies, rule breaks and strategy use (please contact the authors for further details regarding the manual: firstname.lastname@example.org).
Virtual MET (VMET) (Rand, Rukan, Weiss & Katz, 2009)
The VMET was developed within the Virtual Mall, a functional video-capture virtual shopping environment that consists of a large supermarket with 9 aisles. The system includes a single camera that films the user and displays his/her image within the virtual environment. The VMET is a complex shopping task that includes the same number of tasks (items to be bought and information to be obtained) as the MET-HV. However, the client is required to check the contents of the shopping cart at a particular time instead of meeting the tester at a certain time. Virtual reality enables the assessor to objectively measure the client’s behaviour in a safe, controlled and ecologically valid environment. It enables repeated learning trials and adaptability of the environment and task according to the client’s needs.
What to consider before beginning
The MET is performed in a real-world shopping area that allows for minor unpredicted events to occur.
The BMET takes approximately 60 minutes to administer (Dawson et al., 2009).
It is advised that the assessor reads the test manual and becomes familiar with the procedures for test administration and scoring.
Access to a shopping precinct or virtual shopping environment
Pen and paper
Instruction sheet (according to version being used)
Can be used with:
The MET has been tested on populations with acquired brain injury including stroke.
Should not be used with:
The MET cannot be administered to patients who are confined to bed.
Participants require sufficient language skills.
Some tasks may need to be adapted depending on the rehabilitation setting.
The MET was developed in English.