Kettle Test (KT)

Purpose

The Kettle Test was developed as a brief performance-based measure designed to assess cognitive skills in a functional context.

In-Depth Review

Purpose of the measure

The Kettle Test was developed as a brief performance-based measure designed to assess cognitive skills in a functional context. The Kettle Test can be used to evaluate the capacity for independent community living in clients with cognitive impairments. Using the functional task of preparing a hot beverage, the cognitive-functional and problem-solving"Goal-directed cognitive activity that arises in situations for which no response is immediately apparent or available" (Luria, 1966; as cited in (Rath et al., 2004))
skills of the client are assessed.

Available versions

The Kettle Test was developed by Dr. Adina Hartman-Maeir, Nira Armon and Dr. Noomi Katz in 2005, and later validated (Hartman-Maeir, Harel & Katz, 2009).

Features of the measure

Items:

The task of preparing two hot beverages is broken down into 13 discrete steps that can be evaluated. These items are described below.

Description of task

The client prepares two cups of hot beverages – one for him/herself and another for the examiner. The examiner asks the client to prepare a hot drink that differs in two ingredients from the one the client chose for him/her self.

1. Opening the water faucet
2. Filling the kettle with approximately 2 cups of water
3. Turning off the faucet
4. Assembling the kettle
5. Attaching the electric cord to the kettle
6. Plugging the electric cord in an electric socket
7. Turning on the kettle
8. Assembling the ingredients
9. Putting the ingredients into the cups
10. Picking up the kettle when water boils.
11. Pouring the water into the cups.
12. Adding milk
13. Indication of task completion (e.g. verbal, gesture, serving)

What to consider before beginning:

The kettle must be dissembled and equipment set up.

Scoring and Score Interpretation:

All 13 discrete steps of the task are to be scored on a 4-point scale. The total score ranges from 0 to 52 with higher scores indicating the need for greater assistance. The administrator should note any cueing provided to the client in the “comments” section.

The following scoring scale should be used:

• 0 = Performance intact.
• 1 = Item completed independently but completed slowly, by trial and error and/or performance was questionable.
• 2 = Received general cues
• 3 = Received specific cueing; or
  Performance was incomplete (for example, only places part of ingredients in cup, removes the kettle before water boils etc.); or
  Performance is deficient (for example, places lid of kettle upside down, uses wrong ingredients or fails to perform step, for example did not turn on kettle, did not add milk etc.)
• 4 = Received physical demonstration or assistance.

Following performance, the client and administrator are ask to comment on the following:

1. Description of the process by the examiner.
2. Recall of the instructions by the client: “What were the steps you had to do?”
3. The client’s description of the process: “Describe to me what you did from the beginning to the end of the task.”
4. Rating of performance by the client: “How do you rate your performance on this task between 0 to 100 percent?” (If the client cannot rate his/her performance then suggest the following options: “very good”, “fair”, “not so good”, “not good at all”).
5. Rating of difficulty by the client: “How difficult was the task for you? Easy (able to by yourself easily); a little difficult; or very difficult (I needed help)”.
6. Additional comments

Please note that as with most tests that involve everyday problem solving tasks, immediate learning may occur which may impact performance on retesting.

Time:

The average completion time has not been reported, however, it is estimated that the Kettle Test takes approximately 5-20 minutes to complete.

Training requirements:

There is no formal training required to administer the Kettle Test, however the examiner should have some experience and training in observational evaluation of functional performance. Familiarity with the process and scoring is also recommended.

Subscales:

None typically reported.

Equipment:

• Electric kettle: it is important to use a kettle that can be dissembled because assembly of the kettle is part of the task.
• Ingredients for beverages (e.g. instant/decaffeinated coffee, black/herbal tea, sugar/artificial sweeteners, milk, honey)
• Other ingredients (to be used to distract the client, e.g. salt, pepper, oil)
• Tray
• Dishes and utensils for use during the task, plus extra to distract the client (3 cups, milk pitcher, a bowl, 2 plates, 3 tea spoons, a large spoon, 2 forks, a knife, can opener)

Alternative form of the KT

There are no alternative versions of the Kettle Test.

Client suitability

Can be used with:

• Clients with strokeAlso called a “brain attack” and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a “schemic stroke”, or the formation of a blood clot in a vessel supplying blood to the brain., who were living independently in the community prior to strokeAlso called a “brain attack” and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a “schemic stroke”, or the formation of a blood clot in a vessel supplying blood to the brain..
• Clients with strokeAlso called a “brain attack” and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a “schemic stroke”, or the formation of a blood clot in a vessel supplying blood to the brain. who understand spoken or written language.

Should not be used in:

• Clients who do not understand spoken or written language.
• Since the Kettle Test is administered through direction observation of a task a proxy respondent cannot complete it.

In what languages is the measure available?

The manual has only been released in English (Hartman-Maeir, Armon & Katz, 2005), however, only comprehension of spoken language is required of the client during administration.

Summary

What does the tool measure?	The Kettle Test measures cognitive skills in a functional context.
What types of clients can the tool be used for?	Clients with strokeAlso called a “brain attack” and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a “schemic stroke”, or the formation of a blood clot in a vessel supplying blood to the brain. who were living independently in the community prior to strokeAlso called a “brain attack” and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a “schemic stroke”, or the formation of a blood clot in a vessel supplying blood to the brain.
Is this a screeningTesting for disease in people without symptoms. or assessment tool?	Assessment tool
Time to administer	Approximately 5 to 20 minutes.
Versions	There are no alternative versions.
Other Languages	None
Measurement Properties
ReliabilityReliability can be defined in a variety of ways. It is generally understood to be the extent to which a measure is stable or consistent and produces similar results when administered repeatedly. A more technical definition of reliability is that it is the proportion of “true” variation in scores derived from a particular measure. The total variation in any given score may be thought of as consisting of true variation (the variation of interest) and error variation (which includes random error as well as systematic error). True variation is that variation which actually reflects differences in the construct under study, e.g., the actual severity of neurological impairment. Random error refers to “noise” in the scores due to chance factors, e.g., a loud noise distracts a patient thus affecting his performance, which, in turn, affects the score. Systematic error refers to bias that influences scores in a specific direction in a fairly consistent way, e.g., one neurologist in a group tends to rate all patients as being more disabled than do other neurologists in the group. There are many variations on the measurement of reliability including alternate-forms, internal consistency , inter-rater agreement , intra-rater agreement , and test-retest .	Internal consistencyA method of measuring reliability . Internal consistency reflects the extent to which items of a test measure various aspects of the same characteristic and nothing else. Internal consistency coefficients can take on values from 0 to 1. Higher values represent higher levels of internal consistency.: No studies have examined the internal consistencyA method of measuring reliability . Internal consistency reflects the extent to which items of a test measure various aspects of the same characteristic and nothing else. Internal consistency coefficients can take on values from 0 to 1. Higher values represent higher levels of internal consistency. of the Kettle Test. Test-retest: No studies have examined the test-retest reliabilityA way of estimating the reliability of a scale in which individuals are administered the same scale on two different occasions and then the two scores are assessed for consistency. This method of evaluating reliability is appropriate only if the phenomenon that the scale measures is known to be stable over the interval between assessments. If the phenomenon being measured fluctuates substantially over time, then the test-retest paradigm may significantly underestimate reliability. In using test-retest reliability, the investigator needs to take into account the possibility of practice effects, which can artificially inflate the estimate of reliability (National Multiple Sclerosis Society). of the Kettle Test. Intra-rater: No studies have examined the intra-rater reliabilityThis is a type of reliability assessment in which the same assessment is completed by the same rater on two or more occasions. These different ratings are then compared, generally by means of correlation. Since the same individual is completing both assessments, the rater’s subsequent ratings are contaminated by knowledge of earlier ratings. of the Kettle Test. Inter-rater: One study examined the inter-rater reliabilityA method of measuring reliability . Inter-rater reliability determines the extent to which two or more raters obtain the same result when using the same instrument to measure a concept. of the Kettle Test and reported excellent inter-rater.
ValidityThe degree to which an assessment measures what it is supposed to measure.	Construct: Convergent: One study reported excellent correlationThe extent to which two or more variables are associated with one another. A correlation can be positive (as one variable increases, the other also increases – for example height and weight typically represent a positive correlation) or negative (as one variable increases, the other decreases – for example as the cost of gasoline goes higher, the number of miles driven decreases. There are a wide variety of methods for measuring correlation including: intraclass correlation coefficients (ICC), the Pearson product-moment correlation coefficient, and the Spearman rank-order correlation. with the Functional Independence Measure (FIM) Cognitive scale and adequate correlationThe extent to which two or more variables are associated with one another. A correlation can be positive (as one variable increases, the other also increases – for example height and weight typically represent a positive correlation) or negative (as one variable increases, the other decreases – for example as the cost of gasoline goes higher, the number of miles driven decreases. There are a wide variety of methods for measuring correlation including: intraclass correlation coefficients (ICC), the Pearson product-moment correlation coefficient, and the Spearman rank-order correlation. with the Mini-Mental Status Examination (MMSE), Clock Drawing Test and the Behavioural Inattention Test (BIT) Star Cancellation subtest. Known groups: The Kettle Test was able to discriminate clients with strokeAlso called a “brain attack” and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a “schemic stroke”, or the formation of a blood clot in a vessel supplying blood to the brain. from healthy controls.
Floor/Ceiling Effects	Not yet examined in a strokeAlso called a “brain attack” and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a “schemic stroke”, or the formation of a blood clot in a vessel supplying blood to the brain. population.
Does the tool detect change in patients?	Not yet examined in a strokeAlso called a “brain attack” and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a “schemic stroke”, or the formation of a blood clot in a vessel supplying blood to the brain. population.
Acceptability	The Kettle Test is accepted by clients with strokeAlso called a “brain attack” and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a “schemic stroke”, or the formation of a blood clot in a vessel supplying blood to the brain. as it involves a real-life functional task.
Feasibility	The administration of the Kettle Test is easy and quick to perform.
How to obtain the tool?	A preliminary version of the Kettle Test manual can be obtained from: https://www.sralab.org/rehabilitation-measures/kettle-test

Psychometric Properties

Overview

We conducted a literature search to identify all relevant publications on the psychometric properties of the Kettle Test. We identified only one study on the psychometric properties of the Kettle Test, which was published in part by the developers of the measure. More studies are required before definitive conclusions can be drawn regarding the reliabilityReliability can be defined in a variety of ways. It is generally understood to be the extent to which a measure is stable or consistent and produces similar results when administered repeatedly. A more technical definition of reliability is that it is the proportion of "true" variation in scores derived from a particular measure. The total variation in any given score may be thought of as consisting of true variation (the variation of interest) and error variation (which includes random error as well as systematic error). True variation is that variation which actually reflects differences in the construct under study, e.g., the actual severity of neurological impairment. Random error refers to "noise" in the scores due to chance factors, e.g., a loud noise distracts a patient thus affecting his performance, which, in turn, affects the score. Systematic error refers to bias that influences scores in a specific direction in a fairly consistent way, e.g., one neurologist in a group tends to rate all patients as being more disabled than do other neurologists in the group. There are many variations on the measurement of reliability including alternate-forms, internal consistency , inter-rater agreement , intra-rater agreement , and test-retest .
and validityThe degree to which an assessment measures what it is supposed to measure.
of the Kettle Test.

Floor/Ceiling Effects

Not yet examined in a strokeAlso called a "brain attack" and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a "schemic stroke", or the formation of a blood clot in a vessel supplying blood to the brain. population.

Reliability

Internal ConsistencyA method of measuring reliability . Internal consistency reflects the extent to which items of a test measure various aspects of the same characteristic and nothing else. Internal consistency coefficients can take on values from 0 to 1. Higher values represent higher levels of internal consistency.:
Not yet examined in a strokeAlso called a “brain attack” and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a “schemic stroke”, or the formation of a blood clot in a vessel supplying blood to the brain. population.

Test-retest:
Not yet examined in a strokeAlso called a “brain attack” and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a “schemic stroke”, or the formation of a blood clot in a vessel supplying blood to the brain. population.

Intra-rater:
Not yet examined in a strokeAlso called a “brain attack” and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a “schemic stroke”, or the formation of a blood clot in a vessel supplying blood to the brain. population.

Inter-rater:
Hartman-Maeir, Harel & Katz (2009) examined the inter-rater reliabilityA method of measuring reliability . Inter-rater reliability determines the extent to which two or more raters obtain the same result when using the same instrument to measure a concept.
of the Kettle Test in 21 clients with strokeAlso called a "brain attack" and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a "schemic stroke", or the formation of a blood clot in a vessel supplying blood to the brain. admitted to one of two rehabilitation hospitals. Clients were within 1-month post strokeAlso called a "brain attack" and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a "schemic stroke", or the formation of a blood clot in a vessel supplying blood to the brain. and had been living independently prior to stroke. Inter-rater reliabilityA method of measuring reliability . Inter-rater reliability determines the extent to which two or more raters obtain the same result when using the same instrument to measure a concept.
between four Occupational Therapists, as measured using Spearman correlationThe extent to which two or more variables are associated with one another. A correlation can be positive (as one variable increases, the other also increases - for example height and weight typically represent a positive correlation) or negative (as one variable increases, the other decreases - for example as the cost of gasoline goes higher, the number of miles driven decreases. There are a wide variety of methods for measuring correlation including: intraclass correlation coefficients (ICC), the Pearson product-moment correlation coefficient, and the Spearman rank-order correlation.
coefficient was found to be excellent at both sites (r=.851, p=.001; and r=.916, p=.000).

Validity

Content:

Not yet examined in a strokeAlso called a "brain attack" and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a "schemic stroke", or the formation of a blood clot in a vessel supplying blood to the brain. population.

Criterion:

Concurrent:
Not yet examined in a strokeAlso called a "brain attack" and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a "schemic stroke", or the formation of a blood clot in a vessel supplying blood to the brain. population.

Predictive:
Not yet examined in a strokeAlso called a "brain attack" and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a "schemic stroke", or the formation of a blood clot in a vessel supplying blood to the brain. population.

Construct:

Convergent/Discriminant:
Hartman-Maeir, Harel & Katz (2009) examined the convergent validityA type of validity that is determined by hypothesizing and examining the overlap between two or more tests that presumably measure the same construct. In other words, convergent validity is used to evaluate the degree to which two or more measures that theoretically should be related to each other are, in fact, observed to be related to each other.
of the Kettle Test by comparing it to other commonly used measures of cognitive ability in 36 clients with strokeAlso called a “brain attack” and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a “schemic stroke”, or the formation of a blood clot in a vessel supplying blood to the brain. and 36 healthy controls. Correlations were calculated using Pearson CorrelationThe extent to which two or more variables are associated with one another. A correlation can be positive (as one variable increases, the other also increases – for example height and weight typically represent a positive correlation) or negative (as one variable increases, the other decreases – for example as the cost of gasoline goes higher, the number of miles driven decreases. There are a wide variety of methods for measuring correlation including: intraclass correlation coefficients (ICC), the Pearson product-moment correlation coefficient, and the Spearman rank-order correlation.
Coefficients. Excellent correlationThe extent to which two or more variables are associated with one another. A correlation can be positive (as one variable increases, the other also increases – for example height and weight typically represent a positive correlation) or negative (as one variable increases, the other decreases – for example as the cost of gasoline goes higher, the number of miles driven decreases. There are a wide variety of methods for measuring correlation including: intraclass correlation coefficients (ICC), the Pearson product-moment correlation coefficient, and the Spearman rank-order correlation.
was found between the Kettle Test and the Cognitive domain of the Functional Independence Measure (FIM) (r=-.659). Adequate correlations were found between the Kettle Test and the Mini-Mental Status Examination (MMSE), Clock Drawing Test and the Behavioural Inattention Test (BIT) Star Cancellation subtest (r=-.478; r=-.566; and r=-.578 respectively).

Known groups:
Hartman-Maeir, Harel & Katz (2009) verified the ability of the Kettle Test to discriminate between healthy controls (n=36) and individuals with strokeAlso called a "brain attack" and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a "schemic stroke", or the formation of a blood clot in a vessel supplying blood to the brain. (n=36). The healthy controls showed little variability in performance and all scored within a narrow range of 0 to 3 points. The individuals with strokeAlso called a "brain attack" and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a "schemic stroke", or the formation of a blood clot in a vessel supplying blood to the brain. demonstrated great variability in performance and scored within a large range of 1 to 29 points (with higher scores indicating greater need for assistance). The patients with strokeAlso called a "brain attack" and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a "schemic stroke", or the formation of a blood clot in a vessel supplying blood to the brain. required significantly more assistance in completing the Kettle Test whereas the healthy controls required very minimal to no assistance.

Ecological:

Hartman-Maeir, Harel & Katz (2009) investigated the ecological validityRefers to the extent to which a measure captures behaviours that are reflective of those that would occur in a natural setting
of the Kettle Test in 36 patients with strokeAlso called a "brain attack" and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a "schemic stroke", or the formation of a blood clot in a vessel supplying blood to the brain.. Basic activitiesAs defined by the International Classification of Functioning, Disability and Health, activity is the performance of a task or action by an individual. Activity limitations are difficulties in performance of activities. These are also referred to as function.
of daily living (BADL) and safety were measured prior to discharge home, using the Motor domain of the Functional Independence Measure (FIM) and the Safety Rating Scale portion of the Routine Task Inventory (RTI-E) (Allen, 1989; Katz 2006). One month later instrumental activities of daily living (IADL)Complex tasks that involve social or societal issues (shopping, bill paying, cooking, housework, etc.) that are done on a regular basis. were assessed using the IADL Scale (Lawton & Brody, 1969). The Kettle Test was found to have excellent correlationThe extent to which two or more variables are associated with one another. A correlation can be positive (as one variable increases, the other also increases - for example height and weight typically represent a positive correlation) or negative (as one variable increases, the other decreases - for example as the cost of gasoline goes higher, the number of miles driven decreases. There are a wide variety of methods for measuring correlation including: intraclass correlation coefficients (ICC), the Pearson product-moment correlation coefficient, and the Spearman rank-order correlation.
with the Motor domain of the FIM (r=-.759) and adequate correlationThe extent to which two or more variables are associated with one another. A correlation can be positive (as one variable increases, the other also increases - for example height and weight typically represent a positive correlation) or negative (as one variable increases, the other decreases - for example as the cost of gasoline goes higher, the number of miles driven decreases. There are a wide variety of methods for measuring correlation including: intraclass correlation coefficients (ICC), the Pearson product-moment correlation coefficient, and the Spearman rank-order correlation.
with the Safety Rating Scale of the RTI-E and the IADL Scale (r=-.571 and r=-.505 respectively), using Pearson correlationThe extent to which two or more variables are associated with one another. A correlation can be positive (as one variable increases, the other also increases - for example height and weight typically represent a positive correlation) or negative (as one variable increases, the other decreases - for example as the cost of gasoline goes higher, the number of miles driven decreases. There are a wide variety of methods for measuring correlation including: intraclass correlation coefficients (ICC), the Pearson product-moment correlation coefficient, and the Spearman rank-order correlation.
coefficients. The results of this study suggest that performance on the Kettle Test is representative of the functional outcome of patients who are discharged to home.

Responsiveness

Not yet examined in a strokeAlso called a “brain attack” and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a “schemic stroke”, or the formation of a blood clot in a vessel supplying blood to the brain. population.

References

• Hartman-Maeir, A., Armon, N. & Katz, N. (2005). The Kettle Test: A cognitive functional screening test. Unpublished protocol. Helene University, Jerusalem, Israel. Retrieved on February 1, 2010 from: http://www.rehabmeasures.org/Lists/RehabMeasures/DispForm.aspx?ID=939
• Hartman-Maeir, A., Harel, H. & Katz, N. (2009). Kettle Test – A brief measure of cognitive functional performance: Reliability and validity in a stroke population. American Journal of Occupational Therapy, 64, 592-599.

See the measure

How to obtain the Kettle Test?

https://www.sralab.org/rehabilitation-measures/kettle-test