Small-cell

lung

cancer

patients

are

just

a

little

bit

tired

response

shift

and

self-presentation

in

the

measurement

of

fatigue

Background

Response

shift

has

gained

increasing

attention

in

the

measurement

of

health-related

quality

of

life

-LRB-

QoL

-RRB-

as

it

may

explain

counter-intuitive

findings

as

a

result

of

adaptation

to

deteriorating

health

Introduction

Quality

of

life

-LRB-

QoL

-RRB-

is

considered

an

important

treatment

outcome

when

the

treatment

intent

is

not

curative

but

palliative

However

the

expected

deterioration

in

QoL

often

does

not

occur

even

in

cases

of

serious

illness

For

example

Groen

et

al.

studied

patients

with

inoperable

non-small

cell

lung

cancer

treated

by

radiation

with

and

without

chemotherapy

-LSB-

-RSB-

QoL

was

measured

with

The

European

Organization

for

Research

and

Treatment

of

Cancer

Core

Quality

of

Life

Questionnaire

-LRB-

EORTC

-RRB-

-LSB-

-RSB-

which

has

been

designed

specifically

for

use

in

clinical

trials

focusing

on

cancer

patients

However

contrary

to

expectation

they

did

not

find

significant

deterioration

in

the

scale

scores

over

the

treatment

period

of

weeks

Although

cancer

patients

are

willing

to

undergo

risky

and

toxic

treatments

-LSB-

-RSB-

it

seemed

implausible

that

the

side-effects

of

treatment

had

not

affected

their

QoL

Other

studies

also

reported

counter-intuitive

results

For

example

patients

with

a

life-threatening

disease

or

disability

were

found

to

report

stable

QoL

and

patients

with

a

severe

chronic

illness

reported

QoL

levels

that

were

not

inferior

to

that

of

patients

with

a

less

severe

illness

or

to

healthy

patients

-LSB-

-RSB-

Such

counter-intuitive

findings

labelled

by

Breetvelt

and

Van

Dam

as

underreporting

of

problems

suggest

that

patients

report

less

distress

and

dissatisfaction

than

they

actually

feel

-LSB-

-RSB-

In

recent

years

response

shift

theory

has

gained

increasing

attention

in

explaining

paradoxical

and

counter-intuitive

findings

Response

shift

refers

to

a

change

in

internal

standards

values

and

conceptualization

of

QoL

and

is

recognized

as

an

important

mediator

in

adaptation

to

changing

health

-LSB-

-RSB-

However

despite

the

explanatory

power

of

response

shift

theory

our

current

understanding

of

phenomena

that

can

complicate

the

interpretation

of

QoL

scores

is

still

limited

Therefore

we

investigated

QoL

measurement

in

small-cell

lung

cancer

-LRB-

SCLC

-RRB-

patients

during

line

chemotherapy

We

were

quite

surprised

when

we

noticed

discrepancies

between

levels

of

fatigue

measured

with

the

questionnaire

and

answers

spontaneously

reported

during

the

interview

We

therefore

investigated

these

conflicting

findings

in

the

measurement

of

QoL

in

more

depth

This

paper

reports

the

results

of

an

exploratory

longitudinal

multiple-case

study

in

which

we

focused

on

how

patients

responded

to

the

EORTC

question

were

you

tired

at

different

points

in

their

treatment

trajectory

We

aimed

to

describe

the

patients

explanations

when

answering

the

question

and

to

search

for

explanations

of

counter-intuitive

findings

Methods

Procedures

and

study

sample

Between

March

and

September

we

recruited

newly-diagnosed

patients

with

SCLC

who

were

evaluated

for

line

chemotherapy

The

patients

were

attending

one

of

five

outpatient

clinics

for

chest

diseases

in

the

Netherlands

To

maximize

the

likelihood

that

we

would

interview

patients

from

the

beginning

of

their

treatment

we

were

informed

about

new

patients

immediately

after

diagnosis

No

restrictions

were

made

with

regard

to

age

or

treatment

-LRB-

chemotherapy

or

a

combination

of

chemotherapy

and

radiotherapy

-RRB-

Participating

patients

gave

written

consent

and

were

interviewed

at

equivalent

points

in

the

treatment

trajectory

The

first

interview

-LRB-

-RRB-

was

carried

out

at

the

start

of

chemotherapy

In

the

original

plan

the

second

interview

was

planned

after

completion

of

the

course

of

chemotherapy

However

after

inclusion

and

first

interviews

of

patients

we

made

a

decision

to

interview

the

patients

during

treatment

as

well

Therefore

the

second

interview

-LRB-

-RRB-

was

conducted

weeks

after

and

the

third

-LRB-

-RRB-

days

after

completion

of

the

treatment

with

chemotherapy

and

the

fourth

-LRB-

-RRB-

weeks

later

Approval

for

this

study

was

obtained

from

the

Medical

Ethics

Committees

of

the

research

site

and

the

participating

hospitals

During

the

course

of

the

study

eligible

patients

were

invited

to

the

study

Four

patients

were

unwilling

to

participate

died

before

informed

consent

could

be

obtained

and

were

not

interviewed

because

of

imminent

death

Of

the

respondents

who

were

interviewed

were

excluded

from

further

analysis

because

their

data

were

incomplete

i.e.

they

were

only

interviewed

once

-LRB-

six

died

within

a

month

after

and

two

were

too

sick

at

and

died

before

the

end

of

the

planned

chemotherapy

-RRB-

Consequently

the

final

study

sample

consisted

of

SCLC

patients

of

whom

had

limited

-LRB-

male

and

female

mean

age

range

-RRB-

and

had

extended

disease

-LRB-

male

and

female

mean

age

range

-RRB-

All

patients

received

standard

chemotherapy

except

for

patients

whose

chemotherapy

was

combined

with

local

radiation

of

the

tumour

The

majority

of

the

patients

were

married

-LRB-

-RRB-

and

had

children

-LRB-

-RRB-

Of

the

patients

in

our

study

sample

were

interviewed

four

times

were

interviewed

three

times

and

one

patient

was

only

interviewed

twice

resulting

in

a

total

of

interviews

The

interviews

were

conducted

by

MW

in

the

homes

of

the

patients

In

three

cases

the

interview

was

held

in

the

hospital

Interviews

averaged

min

Materials

and

qualitative

method

In

this

exploratory

longitudinal

multiple-case

study

QoL

was

assessed

with

EORTC

-LRB-

version

-RRB-

-LSB-

-RSB-

and

the

lung

cancer

module

-LSB-

-RSB-

The

EORTC

is

the

most

widely

used

cancer-specific

QoL

instrument

in

European

clinical

trials

The

questionnaire

is

composed

of

several

scales

which

measure

among

others

physical

function

mental

health

general

health

and

global

QoL

Furthermore

it

measures

different

symptoms

such

as

pain

dyspnoea

nausea

and

fatigue

The

Fatigue

Scale

consists

of

items

did

you

need

to

rest

have

you

felt

weak

and

were

you

tired

-LRB-

respectively

questions

and

-RRB-

for

which

there

are

response

categories

not

at

all

a

little

quite

a

bit

and

very

much

-LRB-

respectively

scores

and

-RRB-

The

EORTC

and

were

completed

in

combination

with

the

Three-Step

Test-Interview

-LRB-

TSTI

-RRB-

to

investigate

how

respondents

interpreted

the

items

and

how

they

responded

to

them

The

TSTI

consists

of

the

following

steps

-LSB-

-RSB-

-LRB-

-RRB-

concurrent

think

aloud

aimed

at

collecting

observational

data

on

how

a

respondent

completes

the

questionnaire

expressing

his

thoughts

aloud

-LRB-

-RRB-

focused

interview

aimed

at

clarifying

respondents

previous

expressions

while

completing

the

questionnaire

-LRB-

-RRB-

semi-structured

interview

aimed

at

eliciting

respondents

experiences

and

opinions

with

regard

to

the

questionnaire

Interview

protocol

Each

interview

was

conducted

in

an

identical

format

At

QoL

was

measured

with

the

EORTC

followed

by

the

lung

cancer

module

The

questionnaire

was

conducted

in

a

concurrent

think

aloud

manner

and

after

completion

respondents

were

asked

to

clarify

previous

hesitations

expressions

when

rating

certain

items

and

experiences

-LRB-

i.e.

second

and

third

step

of

the

TSTI

-RRB-

Individual

QoL

was

then

measured

with

the

Schedule

for

the

Evaluation

of

Individual

Quality

of

Life

Direct

Weighting

-LRB-

SEIQoL-DW

-RRB-

-LSB-

-RSB-

Finally

we

encouraged

patients

to

talk

freely

about

the

impact

of

diagnosis

and

treatment

At

follow-up

-LRB-

i.e.

and

-RRB-

after

the

SEIQoL-DW

assessment

the

EORTC

questionnaires

were

administered

a

second

time

as

a

so-called

then-test

-LSB-

-RSB-

-LRB-

i.e.

the

patients

filled

out

the

questionnaire

in

reference

to

how

they

perceived

themselves

as

they

were

in

the

previous

interview

-RRB-

In

these

and

following

interviews

EORTC

assessments

were

conducted

in

a

concurrent

think

aloud

manner

and

with

the

second

step

of

TSTI

integrated

in

the

assessment

In

fact

we

encouraged

patients

to

think

aloud

and

we

probed

for

clarification

after

each

item

in

the

case

of

extra

information

was

considered

useful

to

understand

patients

answer

We

used

a

flexible

approach

in

order

not

to

interrupt

the

natural

flow

of

both

the

assessment

as

well

as

the

patient-interviewer

communication

The

interviews

were

audio-taped

and

transcribed

verbatim

In

this

article

we

focus

on

the

EORTC

question

were

you

tired

Analysis

Three

types

of

data

were

collected

and

used

for

analysis

-LSB-

-RSB-

-LRB-

-RRB-

completed

EORTC

questionnaires

-LRB-

-RRB-

-LRB-

-RRB-

observed

respondent

behaviour

recorded

in

field

notes

and

-LRB-

-RRB-

transcriptions

of

the

interviews

including

think

aloud

The

analysis

was

aimed

at

identifying

discrepancies

response

strategies

and

explanations

of

response

behaviour

We

used

the

qualitative

computer

package

Kwalitan

-LRB-

-RRB-

to

extract

relevant

parts

of

the

transcriptions

-LRB-

-RRB-

think

aloud

of

the

question

were

you

tired

and

of

other

items

that

were

useful

in

understanding

the

response

behaviour

to

the

question

on

fatigue

-LRB-

i.e.

two

other

items

of

the

fatigue

scale

the

general

health

and

the

global

QoL

question

of

the

-RRB-

and

-LRB-

-RRB-

comments

related

to

fatigue

symptoms

impact

of

treatment

on

perceived

QoL

and

attitudes

towards

life

In

order

to

deal

with

the

still

remaining

large

amount

of

extracted

data

two

of

the

authors

-LRB-

MW

AT

-RRB-

condensed

extracted

transcripts

of

the

comments

into

core

texts

For

each

patient

the

data

-LRB-

i.e.

think

aloud

combined

with

scores

and

core

texts

of

comments

-RRB-

were

organized

per

interview

in

one

mind

map

-LRB-

see

example

in

Fig.

-RRB-

by

means

of

the

computer

package

Mindjet

Mindmanager

Pro

-LRB-

-RRB-

Fig.

by

means

of

a

mind

map

Branch

EORTC

scores

of

GH/QOL

and

the

fatigue

scale

are

organized

per

interview

and

complemented

by

the

think

aloud

data

Branch

Comments

core

texts

of

relevant

parts

of

transcripts

are

organized

per

code

and

per

interview

Note

-LRB-

-RRB-

not

all

branches

of

the

different

interview

moments

are

shown

Furthermore

a

different

mind

map

was

made

to

organize

think

aloud

data

related

to

the

question

were

you

tired

for

all

patients

per

response

category

per

assessment

including

then-test

For

the

analysis

three

authors

-LRB-

MW

AT

TH

-RRB-

each

independently

read

the

mind

maps

of

each

patient

They

studied

patients

scores

their

think

aloud

responses

and

examined

whether

response

shift

type

explanations

would

be

provided

recalibration

-LRB-

i.e.

using

different

standards

of

comparison

to

assess

fatigue

over

time

-RRB-

reprioritization

-LRB-

i.e.

changes

in

the

importance

attached

to

fatigue

over

time

-RRB-

and

reconceptualization

-LRB-

i.e.

changes

in

the

meaning

of

fatigue

over

time

-RRB-

Two

researchers

-LRB-

MW

AT

-RRB-

searched

for

additional

explanations

in

the

core

texts

to

account

for

the

response

behaviour

and

the

discrepancies

The

research

team

-LRB-

MW

AT

TH

MS

-RRB-

discussed

critically

the

different

response

strategies

used

by

the

patients

and

the

robustness

of

the

interpretations

of

response

shift

Results

Patients

with

or

without

discrepancies

Of

the

patients

-LRB-

male

and

female

age

-RRB-

showed

discrepancies

at

least

at

one

measurement

point

i.e.

differences

between

their

answer

to

the

EORTC

question

were

you

tired

and

their

level

of

fatigue

spontaneously

reported

during

the

interview

In

their

answers

to

the

EORTC

questionnaire

they

all

presented

themselves

positively

and

said

that

they

were

not

tired

Mary

for

example

was

years

old

at

the

time

of

the

first

interview

During

all

her

interviews

she

reported

that

she

was

tired

but

she

consistently

answered

not

at

all

to

the

EORTC

question

-LRB-

Box

-RRB-

Only

once

she

scored

a

little

bit

This

was

at

when

filling

in

her

questionnaire

as

a

then-test

for

and

she

commented

a

little

more

than

at

the

moment

Box

of

a

patient

with

discrepancies

in

reported

level

of

fatiguePatient

MaryMary

was

years

old

and

married

She

had

two

sons

and

two

grandchildren

Her

answer

to

the

EORTC

question

was

consistently

not

at

all

except

for

the

then-test

concerning

the

interview

This

suggests

that

she

did

not

suffer

from

fatigue

in

the

week

prior

to

the

interviews

and

that

fatigue

due

to

chemotherapy

did

not

have

any

impact

at

all

on

her

energy

level

But

during

the

interview

she

spontaneously

provided

information

that

indicated

that

chemotherapy

had

an

impact

on

her

life

and

that

she

regularly

suffered

from

EORTC

score

not

at

all

Think

aloud

Were

you

tired

no

not

at

all

no

no

difference

compared

to

the

pastInterview

I

'm

getting

tired

at

the

least

little

EORTC

score

not

at

all

Think

aloud

Not

tired

last

week

not

at

allThink

aloud

then-test

a

little

more

than

at

the

moment.Interview

According

to

the

doctors

the

X-rays

were

very

good

I

'm

very

optimistic

sometimes

I

'm

tired

but

that

's

my

own

fault

I

do

n't

have

as

much

energy

as

I

did

before

I

became

EORTC

score

not

at

all

Think

aloud

Last

week

I

was

n't

tired

it

's

the

second

week

after

my

chemo

not

at

all

tiredThink

aloud

then-test

for

not

at

allInterview

Yes

it

was

my

last

cycle

of

the

chemo

I

was

afraid

that

I

was

n't

going

to

be

able

to

carry

on

through

the

treatment

But

I

managed

okay

I

'm

tired

but

apart

from

that

nothing

at

EORTC

score

not

at

all

Think

aloud

No

I

was

n't

tired

last

week

not

at

allThink

aloud

then-test

for

not

at

allInterview

Now

and

then

I

'm

tired

It

's

different

to

before

my

chemotherapy

Sometimes

I

'm

so

tired

so

tired

more

than

in

the

past

It

comes

suddenly

in

the

middle

of

the

day

For

many

of

our

respondents

every

new

cycle

of

chemotherapy

had

a

more

severe

impact

on

their

energy

level

Therefore

the

highest

level

of

fatigue

was

to

be

expected

after

the

and

last

cycle

of

chemotherapy

at

However

the

patients

with

discrepancies

all

answered

the

question

were

you

tired

with

not

at

all

or

a

little

For

example

during

her

interviews

at

and

Ann

reported

the

growing

impact

of

every

cycle

of

chemotherapy

but

her

answer

to

the

EORTC

question

at

both

interviews

was

a

little

-LRB-

Box

-RRB-

Box

of

a

patient

using

different

response

strategies

comparison

with

more

sick

patients

response

shift

and

self-presentationPatient

AnnAnn

was

years

old

and

living

with

a

partner

She

did

n't

have

any

children.Her

scores

suggest

that

the

chemotherapy

had

a

slight

impact

on

her

energy

level

during

her

treatment

and

a

greater

impact

weeks

after

completion

of

the

treatment

But

the

interview

and

the

think

aloud

provided

information

that

indicated

that

the

chemotherapy

had

a

growing

impact

on

her

life

and

the

score

quite

a

bit

at

was

the

result

of

bad

news

-LRB-

i.e.

a

recurrence

of

the

tumour

-RRB-

Furthermore

her

data

show

examples

of

different

response

strategies

comparison

with

more

sick

patients

and

self-presentation

EORTC

score

not

at

all

Think

aloud

Were

you

tired

in

principle

I

was

n't

tired

I

was

mentally

tired

it

costs

me

a

lot

of

energy

to

talk

with

my

relatives

I

think

you

mean

physically

tired

You

're

tired

in

the

sense

that

you

can

hardly

put

one

foot

in

front

of

the

other

That

's

being

tired

No

I

'm

not

tired.Interview

I

want

to

be

realistic

think

positively

I

try

not

to

worry

there

is

nothing

I

can

do

I

do

n't

know

when

I

will

die

I

get

angry

when

people

are

surprised

if

I

say

I

'm

doing

fine

it

's

my

decision

how

I

'm

EORTC

score

a

little

bit

Think

aloud

I

feel

it

a

little

bit

compared

to

other

people

who

are

very

sick

So

if

I

have

pain

or

when

I

'm

tired

I

say

to

myself

do

n't

complain

so

everything

I

feel

I

only

feel

a

little

I

'm

doing

fine.Think

aloud

then-test

for

a

littleInterview

Yesterday

I

worked

for

three

hours

and

I

was

exhausted

I

went

to

bed

in

the

middle

of

the

day

in

order

to

be

able

to

show

my

friend

that

I

'm

doing

fine

She

has

trouble

in

coping

me

having

EORTC

score

a

little

bit

Think

aloud

A

little

yes

because

I

have

the

feeling

that

I

was

able

to

get

over

itThink

aloud

then-test

for

I

think

that

I

've

said

a

little

last

time

it

felt

a

little

but

I

shift

my

limit

Interview

It

's

a

kind

of

tiredness

I

do

n't

know

I

've

never

been

like

that

To

allow

yourself

to

be

tired

I

think

that

the

story

they

all

tell

that

the

last

cycle

of

chemo

has

the

most

impact

I

think

that

's

very

very

EORTC

score

quite

a

bit

Think

aloud

Yes

I

was

quite

a

bit

tired

but

only

mentally

tired

I

have

to

adjust

to

the

idea

of

a

new

course

of

treatment

and

radiation

My

health

is

excellent

I

'm

able

to

do

everything

I

like

better

than

weeks

ago

But

with

all

the

medicine

I

'm

taking

to

suppress

the

epileptic

fits

I

'm

scared

just

like

after

the

start

of

chemo.Think

aloud

then-test

for

a

little

but

I

am

not

really

sure

the

pain

which

I

had

in

my

ankels

made

me

tired.Interview

The

radiation

will

make

me

tired

but

it

has

not

started

yet

so

I

am

not

tired

yet

Patients

with

discrepancies

were

identified

in

both

stages

of

disease

and

with

both

treatment

regimens

i.e.

patients

-LRB-

LD

n

ED

n

-RRB-

treated

with

chemotherapy

and

LD

patients

treated

with

chemotherapy

and

radiotherapy

During

the

course

of

the

treatment

-LRB-

interviews

-RRB-

they

answered

the

question

were

you

tired

times

with

not

at

all

times

with

a

little

times

with

quite

a

bit

and

twice

with

very

much

-LRB-

see

individual

scores

per

interview

in

Table

-RRB-

Table

-LRB-

then-test

-RRB-

scores

of

patients

answering

the

EORTC

question

were

you

tired

Response

categories

and

are

representing

respectively

the

category

not

at

all

a

little

quite

a

bit

and

very

much

Small-cell

lung

cancer

patients

-LRB-

n

-RRB-

limited

-LRB-

LD

-RRB-

and

extended

-LRB-

ED

-RRB-

disease

receiving

line

chemotherapy

were

interviewed

at

equivalent

points

in

treatment

at

start

of

chemotherapy

-LRB-

-RRB-

weeks

later

-LRB-

-RRB-

at

end

of

chemotherapy

-LRB-

-RRB-

and

weeks

later

-LRB-

-RRB-

and

are

representing

then-test

scores

obtained

at

respectively

and

when

patients

are

asked

to

provide

a

renewed

evaluation

of

their

fatigue

at

the

previous

assessment

Two

groups

were

identified

patients

with

-LRB-

n

-RRB-

and

without

-LRB-

n

-RRB-

discrepancies

between

their

questionnaire

answer

and

fatigue

spontaneously

reported

in

the

interviewPatients

characteristicsNr.M

P

P

P

P

discrepanciesP

P

No

discrepancies

were

identified

in

of

the

patients

-LRB-

LD

n

ED

n

age

-RRB-

They

answered

the

question

were

you

tired

at

the

end

of

chemotherapy

-LRB-

-RRB-

with

quite

a

bit

or

very

much

During

the

course

of

treatment

-LRB-

interviews

-RRB-

these

patients

answered

the

question

twice

with

not

at

all

times

with

a

little

times

with

quite

a

bit

and

times

with

very

much

-LRB-

Table

-RRB-

Then-test

scores

were

dissimilar

with

scores

of

the

previous

assessment

in

out

of

cases

with

higher

then-test

scores

in

cases

Transcripts

showed

that

patients

had

difficulty

remembering

either

the

previous

measurement

point

and/or

their

fatigue

at

that

time

Response

strategies

for

the

four

response

options

The

think

aloud

texts

for

the

response

categories

quite

a

bit

and

very

much

were

minimal

in

the

entire

study

population

Only

a

few

patients

reacted

briefly

during

the

think

aloud

e.g.

quite

a

bit

too

tired

to

keep

my

eyes

open

yes

quite

a

bit

very

tired

and

next

week

it

will

be

better

very

much

The

same

pattern

was

found

in

all

patients

for

all

four

response

options

when

filling

in

the

questionnaire

as

a

then-test

e.g.

a

little

bit

I

think

tired

then

no

and

very

much

However

patients

in

the

group

with

discrepancies

had

much

more

to

say

in

the

conventional

QoL

measurement

when

choosing

the

options

not

at

all

and

a

little

During

think

aloud

they

seemed

to

justify

the

chosen

response

category

They

used

various

strategies

to

moderate

the

impact

of

fatigue

on

their

life

We

summarized

their

strategies

in

four

categories

-LRB-

-RRB-

I

am

not

tired

all

the

time

-LRB-

e.g.

only

in

the

afternoon

-RRB-

-LRB-

-RRB-

I

am

not

really

tired

it

's

something

else

-LRB-

e.g.

it

's

the

flu

-RRB-

-LRB-

-RRB-

I

have

no

problems

with

it

-LRB-

e.g.

I

can

still

cope

with

it

I

do

n't

want

to

exaggerate

-RRB-

-LRB-

-RRB-

I

am

a

little

bit

tired

but

it

is

due

to

something

else

-LRB-

e.g.

I

did

n't

have

a

proper

meal

-RRB-

Many

of

our

respondents

said

that

they

had

expected

to

become

very

tired

as

a

result

of

the

treatment

but

that

they

were

not

as

sick

as

they

had

expected

They

were

very

happy

that

they

were

able

to

cope

with

the

treatment

and

had

adjusted

to

the

situation

A

male

patient

for

example

had

a

score

of

not

at

all

at

and

explained

I

'm

currently

doing

nothing

so

I

'm

not

tired

The

respondents

indicated

that

they

wanted

to

be

honest

when

filling

in

the

questionnaire

and

did

not

want

to

lie

or

to

exaggerate

their

fatigue

and

because

many

patients

were

not

tired

all

the

time

they

considered

a

score

of

not

at

all

or

a

little

to

be

a

suitable

score

-LRB-

Box

-RRB-

Box

of

different

response

strategies

used

by

patients

with

discrepancies

-LRB-

n

-RRB-

Think

aloud

about

the

question

were

you

tired

I

'm

not

tired

all

the

timeI

'm

only

tired

in

the

afternoonNo

not

at

all

I

'm

not

tired

at

the

moment

it

comes

suddenlyI

have

to

be

honest

sometimes

I

'm

tired

I

ca

n't

say

not

at

all

otherwise

I

would

be

lyingI

'm

not

really

tired

it

's

something

elseNo

not

tired

it

's

the

flue

that

's

why

I

'm

tiredIt

's

not

being

tired

you

know

it

's

more

like

being

restlessI

'm

not

physically

tired

I

'm

mentally

tiredActually

I

ca

n't

be

tired

because

the

Hb

level

in

my

blood

is

okayI

've

no

problems

with

itI

'm

currently

doing

nothing

so

I

've

no

problems

I

'm

not

tiredOf

course

you

can

make

yourself

tired

but

I

do

n'tI

can

still

cope

with

it

I

do

n't

want

to

exaggerateI

'm

a

little

bit

tired

but

it

's

due

to

something

elseA

little

but

it

was

my

own

fault

I

did

too

muchI

did

n't

have

a

proper

meal

that

's

why

I

was

tiredI

did

n't

have

my

lady

working

for

me

in

the

house

she

went

on

holidayIt

's

because

I

've

got

problems

with

my

voice

caused

by

the

radiation

Optimism

Most

patients

told

the

interviewer

regularly

that

they

had

adapted

to

the

situation

and

had

changed

their

attitude

towards

a

more

optimistic

perspective

They

were

not

hopeful

immediately

after

diagnosis

but

optimism

about

recovery

increased

when

the

tumour

was

shrinking

Of

the

patients

reported

spontaneously

that

they

were

optimistic

e.g.

I

've

got

good

news

I

'm

as

optimistic

as

can

be

I

'm

full

of

hope

because

I

was

diagnosed

in

an

early

stage

so

I

'm

good

in

time

Furthermore

they

said

that

they

felt

better

off

than

expected

compared

to

patients

who

were

worse

off

e.g.

I

'm

lucky

not

to

be

very

sick

compared

to

the

patients

I

saw

at

the

hospital

Although

they

experienced

the

impact

of

every

new

cycle

of

treatment

as

more

severe

they

said

to

be

able

to

cope

with

the

treatment

and

to

accept

the

side-effects

e.g.

it

's

part

of

the

package

I

'm

willing

to

put

up

with

knowing

the

chemo

is

doing

the

job

properly

Some

patients

were

actually

feeling

better

after

each

cycle

and

happy

that

they

were

still

alive

e.g.

It

was

much

worse

than

I

wanted

to

admit

last

time

I

'm

feeling

much

better

I

've

already

a

couple

of

months

extra

In

contrast

of

the

patients

expressed

pessimistic

feelings

e.g.

I

'm

a

broken

man

hard

work

all

my

life

and

now

I

do

n't

think

I

've

much

time

left

I

'm

a

bit

depressed

when

does

it

stop

if

it

does

n't

stop

it

would

be

better

if

my

life

was

over

No

plans

for

the

future

you

never

know

when

the

tumour

will

come

back

These

patients

all

reported

high

levels

of

fatigue

during

the

course

of

the

treatment

One

patient

did

not

provide

specific

comments

about

optimism

or

pessimism

Response

shift

and

self

presentation

In

both

groups

with

and

without

discrepancies

we

found

patients

who

had

reported

to

have

changed

their

reference

point

after

-LRB-

i.e.

recalibration

in

contrast

to

-RRB-

They

compared

their

fatigue

at

the

second

and

following

interviews

with

that

of

other

patients

e.g.

I

was

tired

yes

but

compared

to

the

patients

I

've

seen

in

the

hospital

I

'm

just

a

little

bit

tired

or

with

the

period

in

which

they

were

more

tired

-LRB-

e.g.

Compared

to

the

first

week

after

chemo

it

's

the

second

now

I

'm

not

tired

-RRB-

In

one

case

a

patient

spontaneously

re-evaluated

her

previous

measurement

I

told

you

that

I

was

really

tired

then

but

compared

to

how

I

'm

feeling

now

it

was

then

just

a

piece

of

a

cake

Another

one

spoke

about

a

shift

of

limits

which

also

suggests

recalibration

I

already

told

you

that

I

would

change

my

standards

We

did

not

find

indications

of

reconceptualization

and

reprioritization

of

fatigue

The

only

exception

was

Ann

who

made

a

distinction

between

being

physically

and

mentally

tired

-LRB-

see

Box

-RRB-

At

she

said

that

she

was

mentally

tired

but

not

physically

and

her

answer

was

not

at

all

Tired

means

that

you

can

hardly

put

one

foot

in

front

of

the

other

At

she

said

that

she

had

recovered

from

chemotherapy

and

was

physically

able

to

do

anything

she

wanted

but

unfortunately

suffered

from

sudden

epileptic

attacks

caused

by

metastases

She

was

feeling

anxious

in

the

same

way

as

at

the

start

of

her

chemotherapy

and

had

to

consider

further

treatment

options

Just

like

in

the

interview

at

she

said

that

she

was

mentally

tired

but

not

physically

However

this

time

her

score

was

quite

a

bit

instead

of

not

at

all

Purely

because

I

was

mentally

tired

last

week

I

have

to

adjust

to

the

idea

of

a

new

course

of

treatment

Actually

I

have

to

admit

that

I

really

am

the

cancer

patient

I

never

wanted

to

be

This

response

pattern

might

be

interpreted

as

reprioritization

-LRB-

i.e.

changes

in

the

importance

attached

to

mental

fatigue

over

time

-RRB-

Box

of

coping

strategies

used

by

patients

with

discrepancies

-LRB-

n

-RRB-

Spontaneously

reported

coping

behaviourProtective

behaviourI

'm

trying

to

avoid

or

minimize

pessimistic

thoughtsI

do

n't

think

about

it

otherwise

I

ca

n't

cope

with

itWe

do

n't

talk

about

it

just

follow

my

every

day

routineI

'm

building

a

wall

around

myselfAssertive

behaviour/power

displayI

'll

show

others

that

I

'm

managing

all

rightYou

have

to

be

positiveYou

have

to

believe

in

yourself

otherwise

you

ca

n't

manage

it

anymoreFighting

the

stigmaI

'm

not

the

cancer

patient

my

neighbour

thinks

I

amThey

think

I

'm

lying

on

my

bed

all

dayPeople

look

at

me

and

give

advice

that

I

do

n't

wantI

have

to

admit

that

I

really

am

a

cancer

patient

I

did

n't

want

to

be

-LRB-

see

patient

Ann

Box

-RRB-

Because

the

above

mentioned

response

shift

type

explanations

could

not

adequately

explain

our

conflicting

findings

in

the

discrepancy

group

we

questioned

Why

are

patients

presenting

themselves

in

the

questionnaire

more

positively

than

in

the

informal

interview

In

our

search

for

an

other

explanation

we

found

that

of

the

patients

with

discrepancies

had

spontaneously

reported

how

they

dealt

with

having

cancer

and

the

perspective

of

a

short

life-expectancy

We

summarized

their

comments

in

three

categories

-LRB-

see

examples

of

coping

strategies

in

Box

-RRB-

-LRB-

-RRB-

Protective

behaviour

-LRB-

e.g.

protecting

themselves

from

harmful

thoughts

-RRB-

-LRB-

-RRB-

Assertive

behaviour/power

display

-LRB-

e.g.

projecting

the

image

of

being

positive

and

managing

all

right

-RRB-

-LRB-

-RRB-

Fighting

the

stigma

-LRB-

e.g.

fighting

against

being

stigmatized

-RRB-

Taking

these

strategies

into

account

we

concluded

that

a

possible

mechanism

underlying

the

discrepancies

in

this

group

was

self-presentation

As

the

questionnaires

are

explicitly

related

to

cancer

and

since

these

patients

want

to

distance

themselves

from

being

reduced

to

only

a

cancer

patient

they

want

to

present

themselves

as

a

person

who

just

happened

to

have

cancer

Therefore

they

applied

various

strategies

to

respond

to

the

question

on

fatigue

in

order

to

produce

a

score

that

was

as

favourable

as

possible

and

presented

themselves

as

positive

and

managing

their

fatigue

Discussion

Two

third

of

the

patients

showed

discrepancies

in

their

reported

level

of

fatigue

They

reported

a

gradual

decrease

in

energy

at

the

end

of

chemotherapy

but

they

were

not

at

all

or

just

a

little

bit

tired

according

to

their

answer

to

the

EORTC

questionnaire

with

underreporting

as

a

result

They

presented

a

positive

image

of

themselves

and

used

various

strategies

to

explain

their

choice

of

response

category

A

predominant

finding

was

that

patients

adopted

a

more

optimistic

perspective

on

the

treatment

Interestingly

this

was

not

exclusively

found

in

the

discrepancy

group

The

same

was

true

for

recalibration

and

for

the

only

indication

of

reprioritization

These

response

shift

type

explanations

did

not

sufficiently

account

for

the

conflicting

findings

in

our

discrepancy

group

Self-presentation

was

found

to

be

an

additional

-LRB-

coping

-RRB-

mechanism

underlying

the

discrepancies

Our

results

suggest

that

patients

are

not

only

concerned

about

the

impression

they

make

on

others

They

try

to

protect

themselves

from

negative

thoughts

and

they

also

feel

the

need

to

be

positive

and

to

distance

themselves

from

the

stereotypical

cancer

patient

With

this

strategy

they

are

more

capable

of

coping

with

a

situation

that

they

can

not

change

The

suggestion

that

self-presentation

is

an

underlying

mechanism

is

supported

for

example

in

the

case

of

Ann

After

a

recurrence

of

the

tumour

she

adopted

the

realistic

perspective

by

admitting

that

she

really

was

the

cancer

patient

which

she

did

not

want

to

be

before

It

seems

that

she

had

given

up

her

attitude

of

showing

others

that

everything

was

all

right

and

for

the

first

time

she

did

not

present

her

self

as

more

positive

than

she

actually

was

as

she

did

before

Self-presentation

-LRB-

also

called

impression

management

-LSB-

-RSB-

-RRB-

is

a

phenomenon

described

by

Leary

et

al.

in

relation

to

health

behaviour

-LSB-

-RSB-

They

discussed

its

implications

for

research

in

health

psychology

Our

study

shows

that

in

addition

to

response

shift

self-presentation

may

explain

unexpected

results

at

least

in

SCLC

patients

The

question

were

you

tired

in

the

does

not

unequivocally

measure

the

impact

of

chemotherapy

on

the

energy

level

of

patients

in

fact

with

their

responses

patients

seem

to

show

how

that

they

are

managing

the

situation

From

our

results

we

can

not

conclude

that

in

the

group

without

discrepancies

self-presentation

is

not

present

at

all

or

that

whenever

self-presentation

occurs

discrepancies

will

also

be

present

However

our

study

does

show

that

self-presentation

affects

QoL

measurement

These

findings

must

be

taken

into

account

when

investigating

and

interpreting

QoL

data

also

in

other

study

populations

Especially

after

diagnosis

and

in

the

initial

phase

of

treatment

self-presentation

might

be

an

important

coping

strategy

In

fact

during

each

phase

in

which

a

new

equilibrium

and

a

new

identity

has

to

be

found

-LRB-

e.g.

after

a

recurrence

of

the

tumour

or

metastases

-RRB-

self-presentation

might

affect

QoL

measurement

O O O O O O O O O O O O O B I O O O O O O B O B I O O O O O O O O O B I I O O O O O O O O O O O O O O O O O O O B I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O B O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

small-cell lung cancer
self-presentation


Evaluating

the

discriminatory

power

of

and

in

a

US

general

population

survey

using

Shannon

's

indices

Objectives

To

compare

quantitatively

the

discriminatory

power

of

the

and

in

terms

of

absolute

and

relative

informativity

using

Shannon

's

indices

Introduction

The

need

for

assessing

health-related

quality

of

life

-LRB-

HRQL

-RRB-

has

brought

forth

hundreds

of

HRQL

instruments

both

generic

and

disease-specific

-LSB-

-RSB-

Generic

instruments

fall

into

two

main

categories

-LRB-

-RRB-

preference-based

health

classification

systems

and

-LRB-

-RRB-

non-preference

based

measures

sometimes

referred

to

as

health

profile

or

psychometric

measures

-LSB-

-RSB-

Preference-based

classification

systems

also

referred

to

as

multi-attribute

utility

instruments

-LRB-

MAUIs

-RRB-

are

standardized

health

state

classifications

that

can

be

used

to

obtain

a

single

summary

index

-LRB-

utility

score

-RRB-

or

so-called

preference

weight

for

different

health

states

At

the

core

of

any

MAUI

is

a

classification

system

consisting

of

multiple

attributes

-LRB-

dimensions

-RRB-

with

ordered

levels

for

each

dimension

Most

MAUIs

are

generic

and

aim

to

cover

the

full

spectrum

of

disease

and

disability

MAUIs

are

widely

used

as

measures

of

health

outcome

and

are

applied

in

clinical

and

economic

evaluation

-LRB-

to

calculate

QALYs

-RRB-

and

in

population

health

surveys

Three

widely

used

MAUIs

are

the

the

Health

Utilities

Index

Mark

-LRB-

-RRB-

and

the

Health

Utilities

Index

Mark

-LRB-

-RRB-

-LSB-

-RSB-

All

three

instruments

have

shown

acceptable

psychometric

properties

as

established

by

conventional

measures

-LSB-

-RSB-

Feasibility

reliability

validity

and

responsiveness

are

important

measurement

properties

in

MAUIs

just

as

they

are

in

non-preference

based

HRQL

and

health

status

measures

such

as

the

However

these

properties

may

be

operationalized

differently

in

MAUIs

compared

to

non-preference

based

measures

-LSB-

-RSB-

An

underlying

property

to

the

concepts

of

reliability

validity

and

responsiveness

is

the

ability

of

an

instrument

to

discriminate

between

-LRB-

true

-RRB-

different

levels

of

health

This

requires

a

MAUI

to

define

the

full

range

of

potential

health

states

and

to

be

sensitive

over

this

range

A

necessary

measurement

property

for

any

health

status

measure

-LRB-

including

MAUIs

-RRB-

is

the

ability

to

discriminate

among

people

at

a

single

point

in

time

This

property

is

sometimes

referred

to

as

sensitivity

or

more

accurately

discriminatory

power

-LSB-

-RSB-

Guyatt

et

al.

-LRB-

-RRB-

proposed

a

reliability

coefficient

as

a

suitable

statistic

to

express

discriminatory

power

-LSB-

-RSB-

Reliability

essentially

reflects

two

different

concepts

-LRB-

-RRB-

consistency

e.g.

between

raters

-LRB-

inter-rater

reliability

-RRB-

or

over

time

-LRB-

test-retest

reliability

-RRB-

and

-LRB-

-RRB-

discriminatory

power

the

ability

of

an

instrument

to

discriminate

among

people

-LSB-

-RSB-

We

propose

Shannon

's

indices

of

informativity

as

suitable

measures

that

solely

reflect

discriminatory

power

-LSB-

-RSB-

Discriminatory

power

of

MAUIs

is

usually

investigated

in

an

informal

and

partial

manner

by

examining

the

frequency

distributions

e.g.

for

floor

or

ceiling

effects

-LSB-

-RSB-

Shannon

's

indices

are

suitable

to

assess

discriminatory

power

in

MAUIs

for

two

reasons

first

they

are

theoretically

based

and

second

they

incorporate

the

frequency

distribution

across

all

categories

of

a

MAUI

's

health

status

classification

system

-LRB-

not

just

the

highest

and

lowest

categories

as

is

the

case

with

ceiling

and

floor

effects

-RRB-

Our

aim

is

to

investigate

the

discriminatory

power

of

the

and

in

a

general

population

sample

as

expressed

by

Shannon

's

indices

Informativity

was

assessed

separately

by

dimension

and

by

MAUI

as

a

whole

Methods

Data

A

publicly

available

dataset

was

used

-LRB-

at

-RRB-

resulting

from

the

US

valuation

study

-LSB-

-RSB-

Collected

data

consisted

of

self-completed

and

data

from

a

sample

of

the

general

adult

US

population

with

an

over-sampling

of

Hispanics

and

non-Hispanic

Blacks

The

data

were

collected

using

a

standardized

questionnaire

from

which

and

health

profiles

were

extracted

using

available

recoding

algorithms

-LSB-

-RSB-

Only

the

responses

of

respondents

who

had

no

missing

data

on

any

of

the

three

instruments

were

included

in

this

study

-LRB-

of

the

total

number

of

respondents

-RRB-

Instruments

The

descriptive

system

consists

of

dimensions

-LRB-

items

-RRB-

with

levels

each

logically

defining

unique

health

states

-LRB-

permutations

-RRB-

The

was

originally

developed

to

assess

outcomes

in

survivors

of

cancer

in

childhood

and

contains

dimensions

-LRB-

excluding

the

original

dimension

of

fertility

-RRB-

with

levels

per

dimension

The

originally

developed

for

a

general

population

health

survey

in

Canada

has

dimensions

with

levels

per

dimension

The

and

descriptive

systems

define

and

unique

health

states

respectively

-LSB-

-RSB-

Table

compares

the

dimensions

common

to

at

least

two

of

the

classification

systems

Mobility/Ambulation

Anxiety/Depression/Emotion

Pain/Discomfort

-LRB-

-RRB-

Self-Care

-LRB-

-RRB-

and

Cognition

-LRB-

-RRB-

Table

descriptions

for

common

dimensions

between

and

problems

in

walking

aboutAble

to

walk

bend

lift

jump

and

run

normally

for

ageAble

to

walk

around

the

neighbourhood

without

difficulty

and

without

walking

equipmentSome

problems

in

walking

aboutWalks

bends

lifts

jumps

or

runs

with

some

limitations

but

does

not

require

helpAble

to

walk

around

the

neighbourhood

with

difficulty

but

does

not

require

walking

equipment

or

the

help

of

another

personConfined

to

bedRequires

mechanical

equipment

-LRB-

such

as

canes

crutches

braces

or

wheelchair

-RRB-

to

walk

or

get

around

independentlyAble

to

walk

around

the

neighbourhood

with

walking

equipment

but

without

the

help

of

another

personRequires

the

help

of

another

person

to

walk

or

get

around

and

requires

mechanical

equipment

as

wellAble

to

walk

only

short

distances

with

walking

equipment

and

requires

a

wheelchair

to

get

around

the

neighbourhoodUnable

to

control

or

use

arms

and

legsUnable

to

walk

alone

even

with

walking

equipment

Able

to

walk

short

distances

with

the

help

of

another

person

and

requires

a

wheelchair

to

get

around

the

neighbourhoodCannot

walk

at

allSelf-careSelf-careNo

problems

with

self-careEats

bathes

dresses

and

uses

the

toilet

normally

for

ageSome

problems

washing

or

dressing

selfEats

bathes

dresses

or

uses

the

toilet

independently

with

difficultyUnable

to

wash

or

dress

selfRequires

mechanical

equipment

to

eat

bathe

dress

or

use

the

toilet

independentlyRequires

the

help

of

another

person

to

eat

bathe

dress

or

use

the

toiletPain/DiscomfortPainPainNo

pain

or

discomfortFree

of

pain

and

discomfortFree

of

pain

and

discomfortModerate

pain

or

discomfortOccasional

pain

Discomfort

relieved

by

non-prescription

drugs

or

self-control

activity

without

disruption

of

normal

activitiesMild

to

moderate

pain

that

prevents

no

activitiesExtreme

pain

or

discomfortFrequent

pain

Discomfort

relieved

by

oral

medicines

with

occasional

disruption

of

normal

activitiesModerate

pain

that

prevents

a

few

activitiesFrequent

pain

frequent

disruption

of

normalactivities

Discomfort

requires

prescription

narcotics

for

reliefModerate

to

severe

pain

that

prevents

some

activitiesSevere

pain

Pain

not

relieved

by

drugs

and

constantly

disrupts

normal

activitiesSevere

pain

that

prevents

most

activitiesAnxiety/DepressionEmotionEmotionNot

anxious

or

depressedGenerally

happy

and

free

from

worryHappy

and

interested

in

lifeModerately

anxious

or

depressedOccasionally

fretful

angry

irritable

anxious

depressed

or

suffering

night

terrors

Somewhat

happyExtremely

anxious

or

depressedOften

fretful

angry

irritable

anxious

depressed

or

suffering

night

terrors

Somewhat

unhappyAlmost

always

fretful

angry

irritable

anxious

depressedVery

unhappyExtremely

fretful

angry

irritable

anxious

or

depressed

usually

requiring

hospitalization

or

psychiatric

institutional

careSo

unhappy

that

life

is

not

worthwhile

CognitionCognitionLearns

and

remembers

school

work

normally

for

ageAble

to

remember

most

things

think

clearly

and

solve

day

to

day

problemsLearns

and

remembers

school

work

more

slowly

than

classmates

as

judged

by

parents

and/or

teachersAble

to

remember

most

things

but

have

a

little

difficulty

when

trying

to

think

and

solve

day

to

day

problemsLearns

and

remembers

very

slowly

and

usually

requires

special

educational

assistanceSomewhat

forgetful

but

able

to

think

clearly

and

solve

day

to

day

problemsUnable

to

learn

and

rememberSomewhat

forgetful

and

have

a

little

difficulty

when

trying

to

think

or

solve

day

to

day

problemsVery

forgetful

and

have

great

difficulty

when

trying

to

think

or

solve

day

to

day

problemsUnable

to

remember

anything

at

all

and

unable

to

think

or

solve

day

to

day

problems

Shannon

's

indices

background

and

properties

The

Shannon

index

named

after

Claude

Shannon

who

is

considered

to

be

the

founder

of

information

theory

was

initially

developed

to

separate

noise

from

information

carrying

signals

in

telecommunication

systems

-LSB-

-RSB-

The

Shannon

index

is

also

known

as

the

Shannon

Weaver

index

because

of

Warren

Weaver

's

contribution

to

Shannon

's

original

paper

and

as

the

Shannon

Wiener

index

named

after

Norbert

Wiener

who

independently

developed

a

concept

similar

to

Shannon

's

-LSB-

-RSB-

The

Shannon

index

has

been

applied

in

a

variety

of

fields

ranging

from

ecology

-LRB-

as

a

measure

of

biodiversity

-RRB-

to

psychology

record

linkage

and

molecular

biology

-LRB-

genetic

diversity

-RRB-

-LSB-

-RSB-

In

information

theory

the

information

of

a

signal

is

distinguished

from

the

meaning

or

the

semantic

content

of

a

signal

Rather

the

information

is

quantified

and

is

identified

with

uncertainty

Informativity

is

dependent

on

the

number

of

classes

-LRB-

e.g.

bits

or

response

options

-RRB-

and

the

distribution

of

the

observations

-LRB-

the

signal

-RRB-

among

classes

For

classifications

this

implies

that

if

one

would

want

to

develop

a

useful

-LRB-

informative

-RRB-

distinction

between

say

European

countries

distinguishing

between

Scandinavian

and

non-Scandinavian

countries

would

be

far

less

informative

than

distinguishing

between

Northern

Western

Eastern

and

Southern

European

countries

Note

that

the

latter

classification

not

only

contains

more

categories

but

the

countries

are

also

more

evenly

distributed

among

categories

The

Shannon

index

is

defined

as

where

H

represents

the

absolute

amount

of

informativity

captured

C

is

the

number

of

possible

categories

-LRB-

levels

or

permutations

in

this

study

-RRB-

and

pi

ni/N

the

proportion

of

observations

in

the

ith

category

-LRB-

i

C

-RRB-

where

ni

is

the

observed

number

of

scores

-LRB-

responses

-RRB-

in

category

i

and

N

is

the

total

sample

size

-LSB-

-RSB-

Any

log

base

can

be

used

as

long

as

one

is

consistent

Using

log

base

as

did

Shannon

allows

the

interpretation

of

the

resulting

units

as

bits

per

individual

The

higher

the

index

H

is

the

more

information

is

captured

by

the

system

In

case

of

a

homogeneous

-LRB-

rectangular

-RRB-

distribution

i.e.

ratings

are

evenly

distributed

among

categories

-LRB-

pi

p

for

all

i

-RRB-

the

optimal

amount

of

information

is

captured

and

H

has

reached

its

maximum

-LRB-

H

max

-RRB-

which

equals

If

the

number

of

categories

-LRB-

C

-RRB-

is

increased

H

max

increases

accordingly

but

H

will

only

increase

if

the

newly

added

categories

are

actually

used

The

variance

of

the

Shannon

index

is

defined

as

-LSB-

-RSB-

Accordingly

standard

errors

and

confidence

intervals

can

be

calculated

The

Shannon

index

combines

the

absolute

information

content

as

expressed

by

the

number

of

categories

with

the

extent

to

which

the

information

is

evenly

spread

over

these

categories

Shannon

's

Evenness

index

-LRB-

J

-RRB-

exclusively

reflects

the

latter

component

i.e.

the

rectangularity

of

a

distribution

This

measure

was

first

proposed

by

Lloyd

and

Ghelardi

-LSB-

-RSB-

Shannon

already

referred

to

it

as

relative

entropy

and

Pielou

termed

the

concept

evenness

-LSB-

-RSB-

Shannon

's

Evenness

index

-LRB-

J

-RRB-

is

defined

as

J

H

H

max

which

expresses

the

use

of

the

system

-LRB-

H

-RRB-

given

its

potential

-LRB-

H

max

-RRB-

Shannon

's

index

H

can

be

considered

as

an

expression

of

the

absolute

informativity

of

a

system

whereas

Shannon

's

Evenness

index

J

expresses

the

relative

informativity

of

a

system

or

evenness

of

a

distribution

regardless

the

number

of

categories

Two

alternative

measures

of

-LRB-

bio

-RRB-

diversity

are

the

Simpson

and

the

Brillouin

index

We

used

the

Shannon

index

since

the

Brillouin

index

is

dependent

on

sample

size

and

the

Simpson

index

gives

very

little

weight

to

categories

that

are

rarely

occupied

-LSB-

-RSB-

Shannon

indices

applied

to

MAUIs

The

basic

characteristics

of

Shannon

's

indices

which

make

them

suitable

to

reflect

discriminatory

power

have

been

documented

and

are

explained

as

follows

In

an

item

where

a

response

option

has

a

very

high

-LRB-

or

low

-RRB-

endorsement

e.g.

p

is

over

-LRB-

or

under

-RRB-

one

learns

very

little

because

one

can

predict

with

more

than

certainty

what

the

answer

will

be

In

other

words

there

is

very

little

information

being

transmitted

Conversely

the

maximum

amount

of

information

-LRB-

uncertainty

-RRB-

is

being

transmitted

when

in

an

item

with

two

response

options

p

is

for

each

response

option

As

described

above

this

characteristic

of

an

even

distribution

underlies

the

Shannon

indices

In

case

of

an

even

distribution

the

item

-LRB-

dimension

-RRB-

is

being

most

efficiently

used

which

means

that

the

discriminant

ability

of

the

level

descriptors

is

maximal

The

Shannon

indices

can

be

calculated

by

dimension

separately

or

by

MAUI

as

a

whole

To

calculate

Shannon

's

indices

by

dimension

levels

are

treated

as

categories

so

C

represents

the

number

of

levels

-LRB-

L

-RRB-

pi

is

the

proportion

of

responses

of

the

ith

level

and

H

max

equals

Suppose

the

Mobility

dimension

is

scored

by

respondents

no

problems

-LRB-

n

-RRB-

some

problems

-LRB-

n

-RRB-

and

confined

to

bed

-LRB-

n

-RRB-

Shannon

's

index

for

Mobility

is

calculated

as

H

-LRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-RRB-

and

H

max

so

J

Figure

illustrates

the

difference

between

absolute

and

relative

informativity

-LRB-

H

evenness

J

-RRB-

relative

to

the

number

of

levels

-LRB-

L

-RRB-

in

a

series

of

hypothetical

health

classification

systems

designed

to

describe

the

same

underlying

dimension

For

illustrative

purposes

we

consider

only

one

dimension

Figure

shows

two

distributions

of

responses

corresponding

to

two

different

classification

systems

both

of

which

have

levels

one

system

results

in

a

skewed

distribution

while

the

other

results

in

a

rectangular

distribution

Assuming

these

responses

are

obtained

within

the

same

population

the

system

that

yields

the

rectangular

distribution

is

superior

in

discriminating

between

patients

and

the

Shannon

indices

have

both

reached

their

maximum

values

Figure

illustrates

the

concept

of

relative

informativity

The

left

panel

shows

the

same

skewed

distribution

as

depicted

in

Figure

the

right

panel

shows

the

same

distribution

of

responses

but

now

as

it

results

from

a

level

classification

system

in

which

levels

and

are

unused

Absolute

informativity

-LRB-

Shannon

's

H

-RRB-

remains

unchanged

but

J

decreases

expressing

lower

relative

informativity

Clearly

adding

extra

levels

that

do

not

represent

anyone

in

the

population

-LRB-

no

individual

shifts

from

a

current

level

to

any

of

the

new

levels

-RRB-

does

not

lead

to

a

gain

in

absolute

informativity

-LRB-

H

-RRB-

while

the

potential

of

a

level

system

is

underutilized

compared

to

a

level

system

which

is

expressed

by

a

lower

J

So

why

not

use

just

the

Shannon

Evenness

index

Figure

shows

the

added

value

of

absolute

informativity

-LRB-

the

H

index

-RRB-

If

the

and

level

systems

both

yield

rectangular

distributions

evenness

J

will

be

the

same

but

obviously

H

increases

since

the

level

system

is

much

more

refined

in

discriminating

between

patients.Fig

of

Absolute

Informativity

-LRB-

H

-RRB-

and

Relative

Informativity

-LRB-

J

-RRB-

with

Skewed

and

Rectangular

Distributions

in

a

Level

System

and

Level

System

To

calculate

Shannon

's

indices

by

instrument

as

a

whole

permutations

are

treated

as

unique

categories

-LRB-

e.g.

categories

for

-RRB-

so

C

is

the

number

of

permutations

-LRB-

Pmax

-RRB-

pi

is

the

proportion

of

the

ith

permutation

and

H

max

now

equals

Since

the

number

of

observations

in

our

study

-LRB-

N

-RRB-

is

lower

than

the

number

of

theoretically

possible

permutations

in

-LRB-

-RRB-

and

-LRB-

-RRB-

maximum

informativity

-LRB-

H

max

-RRB-

in

and

and

consequently

maximum

relative

informativity

J

can

not

be

reached

a

priori

Therefore

Shannon

's

indices

by

MAUI

as

a

whole

were

calculated

using

an

estimation

approach

Assuming

that

the

current

sample

is

representative

subsamples

of

the

original

set

of

observed

health

states

were

drawn

in

order

to

estimate

the

number

of

different

health

states

in

hypothetical

populations

of

and

million

respondents

by

means

of

extrapolation

This

procedure

was

repeated

for

different

proportions

of

the

population

in

relation

to

the

number

of

health

states

-LRB-

e.g.

different

health

states

accounted

for

a

proportion

of

the

respondents

-RRB-

in

order

to

estimate

the

shape

of

the

frequency

distribution

in

the

hypothetical

populations

of

and

million

respondents

Finally

Shannon

's

H

and

J

could

be

calculated

-LRB-

details

can

be

obtained

from

the

authors

-RRB-

Results

The

mean

age

of

the

respondents

was

years

-LRB-

range

years

-RRB-

with

of

the

respondents

being

male

White

-LRB-

non-Hispanic

-RRB-

respondents

were

-LRB-

-RRB-

non-Hispanic

blacks

were

-LRB-

-RRB-

and

Hispanic

were

-LRB-

-RRB-

Table

shows

the

frequencies

of

responses

to

the

and

dimensions

The

dominant

response

was

no

problems

-LRB-

level

-RRB-

for

all

dimensions

in

all

instruments

with

a

proportion

larger

than

for

out

of

dimensions

in

-LRB-

Self-Care

-RRB-

out

of

in

-LRB-

Self-Care

-RRB-

and

out

of

in

-LRB-

Hearing

Speech

Dexterity

-RRB-

In

all

and

dimensions

frequencies

decreased

with

increasing

level

severity

In

the

Cognition

dimension

however

more

respondents

reported

problems

at

level

-LRB-

-RRB-

and

level

-LRB-

-RRB-

than

at

level

-LRB-

-RRB-

Although

small

these

differences

also

occurred

in

the

Vision

and

Hearing

dimensions.Table

distribution

-LRB-

-RRB-

of

responses

to

the

and

instruments

-LRB-

N

-RRB-

Level

Self

Usual

Figure

shows

absolute

informativity

-LRB-

Shannon

's

H

-RRB-

and

relative

informativity

-LRB-

Shannon

's

Evenness

J

-RRB-

of

the

common

dimensions

among

the

three

instruments

Absolute

informativity

-LRB-

H

-RRB-

was

highest

for

in

all

common

dimensions

with

largest

differences

between

and

the

other

two

instruments

in

the

dimensions

Pain/Discomfort

-LRB-

compared

to

compared

to

-RRB-

and

Cognition

-LRB-

compared

to

-RRB-

Fig.

Shannon

Index

-LRB-

H

-RRB-

and

the

Shannon

Evenness

Index

for

the

common

dimensions

between

and

comparison

by

dimension

not

available

Confidence

intervals

had

an

average

range

of

-LRB-

H

-RRB-

and

of

-LRB-

J

-RRB-

Relative

informativity

-LRB-

J

-RRB-

was

highest

for

in

all

common

dimensions

with

largest

differences

with

the

other

two

instruments

in

the

dimensions

Mobility/Ambulation

-LRB-

compared

to

compared

to

-RRB-

and

Anxiety/Depression/Emotion

-LRB-

compared

to

compared

to

-RRB-

Table

shows

Shannon

's

indices

by

classification

system

as

a

whole

The

and

descriptive

systems

distinguished

and

observed

different

unique

health

states

accounting

for

and

of

all

possible

permutations

respectively

The

estimation

procedure

indicated

that

absolute

informativity

was

highest

for

-LRB-

range

-RRB-

followed

by

-LRB-

range

-RRB-

and

lowest

for

-LRB-

range

-RRB-

Relative

informativity

was

highest

in

-LRB-

range

-RRB-

followed

by

-LRB-

range

-RRB-

and

lowest

for

-LRB-

range

-RRB-

Table

's

index

-LRB-

H

-RRB-

and

Shannon

's

evenness

index

-LRB-

J

-RRB-

for

and

Comparison

by

instrument

-LRB-

permutations

-RRB-

Observed

health

EstimationH

J

H

J

H

J

N

N

N

Discussion

We

compared

the

discriminatory

power

of

the

and

in

the

general

population

using

Shannon

's

indices

of

absolute

and

relative

informativity

for

each

dimension

separately

and

by

MAUI

as

a

whole

As

might

be

expected

in

a

general

population

sample

most

respondents

reported

no

problems

on

all

dimensions

and

there

were

fewer

responses

with

increasing

level

severity

An

exception

is

Cognition

where

respondents

reported

more

problems

on

levels

and

than

on

level

This

is

probably

due

to

the

fact

that

this

dimension

is

not

unidimensional

and

levels

and

are

conceptualized

parallel

rather

than

ordinal

That

is

Cognition

level

focuses

on

problems

in

thinking

and

problem

solving

level

addresses

problems

in

remembering

whereas

level

combines

the

problems

mentioned

in

levels

and

Absolute

informativity

by

dimension

was

highest

for

the

descriptive

system

appears

to

underperform

in

the

Pain/Discomfort

dimension

Moreover

appears

to

miss

a

considerable

amount

of

disability

of

the

population

indicated

to

have

no

problems

on

against

on

and

on

-LRB-

Table

-RRB-

Shannon

's

H

translated

this

difference

adequately

-LRB-

Figure

-RRB-

Apparently

for

this

population

the

would

benefit

from

more

levels

on

the

Pain/Discomfort

dimension

Regarding

the

Cognition

dimension

the

difference

in

absolute

informativity

between

and

might

be

explained

by

the

extra

levels

in

but

the

higher

J

value

in

suggests

an

alternative

contributive

factor

One

explanation

may

be

that

Cognition

is

not

unidimensional

and

more

sensitive

to

mild

problems

-LRB-

levels

-RRB-

than

Cognition

-LRB-

level

-RRB-

Another

explanation

could

be

that

the

difference

is

due

to

currently

suboptimal

recoding

algorithms

For

relative

informativity

by

dimension

the

descriptive

system

showed

superior

results

in

Mobility/Ambulation

Self-Care

and

Anxiety/Depression/Emotion

The

large

differences

in

Mobility/Ambulation

could

be

due

to

a

relatively

large

leap

in

the

grading

of

the

level

descriptions

in

Ambulation

where

the

difference

between

level

-LRB-

without

difficulty

-RRB-

and

level

-LRB-

with

difficulty

-RRB-

can

be

considered

disproportionately

large

in

a

level

dimension

The

same

leap

from

level

-LRB-

normal

-RRB-

to

level

-LRB-

with

difficulty

-RRB-

occurs

in

Self-Care

We

found

that

the

level

Self

Care

outperformed

the

level

Self-Care

in

both

absolute

and

relative

informativity

-LRB-

Fig.

-RRB-

which

is

probably

due

to

the

severe

grading

of

level

in

The

difference

in

relative

informativity

between

and

the

HUI

instruments

in

Anxiety/Depression/Emotion

is

probably

due

to

the

extra

levels

in

and

that

are

rarely

endorsed

Overall

performance

in

terms

of

informativity

of

and

of

the

common

dimensions

varies

over

dimensions

The

Pain/Discomfort

dimension

of

but

perhaps

also

other

dimensions

might

benefit

from

an

extension

to

or

levels

and

might

benefit

from

more

sensitive

grading

terms

in

their

level

descriptions

especially

the

threshold

level

in

Ambulation

-LRB-

-RRB-

and

Self-Care

-LRB-

-RRB-

When

assessing

informativity

by

instrument

shows

the

best

results

on

absolute

informativity

but

the

lowest

on

relative

informativity

while

shows

highest

relative

informativity

and

lowest

absolute

informativity

seems

to

be

the

optimal

compromise

The

importance

of

differences

in

the

Shannon

indices

ultimately

requires

empirical

evidence

over

a

wider

range

of

populations

conditions

and

instruments

including

evidence

on

discriminant

validity

As

Shannon

's

indices

are

new

in

the

field

of

health

status

measurement

some

methodological

issues

need

to

be

addressed

taking

into

account

that

their

principal

focus

is

on

classifications

with

mutually

exclusive

categories

rather

than

conventional

-LRB-

health

status

-RRB-

measures

which

by

design

contain

multiple

partially

overlapping

items

The

Shannon

indices

share

some

properties

with

reliability

coefficients

Like

reliability

indices

they

express

discriminatory

power

Furthermore

they

are

also

non-dimensional

i.e.

they

have

no

relation

to

the

content

meaning

or

clinical

relevance

of

what

the

instrument

aims

to

measure

which

make

them

suitable

for

comparability

between

instruments

as

well

as

between

populations

However

reliability

reflects

two

different

concepts

discriminatory

power

as

such

and

consistency

e.g.

consistency

between

raters

-LRB-

inter-rater

reliability

-RRB-

or

consistency

over

time

-LRB-

test-retest

reliability

-RRB-

This

requires

a

repeated

measurement

-LRB-

repetition

over

raters

or

over

time

-RRB-

which

introduces

an

error

component

in

case

of

a

difference

among

the

repeated

measurements

Shannon

's

indices

solely

reflect

discriminatory

power

and

need

only

a

single

measurement

Furthermore

the

Shannon

indices

are

non-parametric

measures

and

therefore

highly

suitable

for

nominal

or

ordinal

measurement

scales

Since

Shannon

's

indices

have

no

dimension

and

are

independent

of

any

external

standard

a

rectangular

distribution

is

always

the

ideal

from

the

perspective

of

informativity

When

comparing

the

discriminatory

power

of

similar

dimensions

of

different

MAUIs

rectangularity

is

always

optimal

as

it

reflects

which

MAUI

is

the

most

sensitive

in

discriminating

between

different

persons

in

that

particular

population

This

implies

that

one

MAUI

can

not

be

superior

in

varying

populations

-LRB-

e.g.

a

general

population

and

a

diseased

population

sample

-RRB-

Furthermore

MAUIs

are

bound

to

score

rather

low

on

discriminatory

power

in

a

general

population

sample

as

the

extreme

categories

which

have

to

be

included

for

coverage

of

the

full

spectrum

of

diseases

will

not

be

endorsed

frequently

Previously

the

common

approach

to

investigate

discriminatory

power

was

examining

the

frequency

distributions

of

responses

e.g.

for

ceiling

or

floor

effects

A

comprehensive

formal

measure

to

express

discriminatory

power

such

as

Shannon

's

indices

seems

clearly

superior

to

such

a

face-value

method

Furthermore

when

the

number

of

categories

is

large

-LRB-

e.g.

when

comparing

MAUIs

as

a

whole

-RRB-

it

becomes

very

difficult

to

make

a

sound

comparison

by

just

looking

at

the

distributions

We

have

demonstrated

the

use

of

the

Shannon

indices

to

compare

the

discriminatory

power

of

different

MAUIs

to

show

which

instrument

is

more

sensitive

in

differentiating

between

levels

of

health

in

the

population

at

hand

But

they

may

also

be

used

to

guide

the

development

of

new

or

optimization

of

existing

MAUIs

by

helping

determine

how

many

levels

are

efficient

for

each

dimension

This

is

a

particularly

relevant

consideration

for

MAUIs

since

adding

extra

levels

in

a

descriptive

system

makes

it

increasingly

complex

and

the

derivation

of

a

robust

set

of

preference

weights

more

challenging

Apart

from

MAUIs

the

Shannon

indices

can

also

be

used

in

a

wide

range

of

other

classifications

in

the

medical

domain

-LRB-

e.g.

the

Karnofsky

scale

the

Spitzer

QL

index

-RRB-

and

in

the

clinical

domain

-LRB-

e.g.

the

APGAR

score

the

Child-Pugh

classification

-RRB-

A

practical

weakness

of

the

Shannon

approach

is

that

when

the

sample

size

is

exceeded

by

the

total

number

of

health

states

described

by

all

permutations

across

all

dimensions

of

a

MAUI

informativity

-LRB-

for

the

instrument

as

a

whole

-RRB-

has

to

be

estimated

This

implies

that

using

the

Shannon

Evenness

index

by

instrument

is

not

very

practical

when

a

health

classification

system

has

a

large

number

of

permutations

as

was

the

case

in

-LRB-

permutations

-RRB-

This

however

is

not

a

disadvantage

of

the

Shannon

methodology

per

se

but

also

a

matter

of

classification

design

-LRB-

overload

of

dimensions

with

detailed

response

options

producing

an

excessive

amount

of

empty

permutations

-RRB-

or

a

practical

problem

-LRB-

excessive

data

collection

-RRB-

From

a

clinical

or

psychometric

perspective

it

may

seem

tempting

to

extend

any

MAUI

with

extra

levels

or

dimensions

as

it

provides

more

clinically

relevant

detail

generally

and

improves

reliability

But

Shannon

's

indices

reveal

that

this

may

not

always

be

a

prudent

approach

Increasing

the

number

of

levels

per

dimension

-LRB-

or

permutations

in

the

entire

system

-RRB-

will

probably

result

in

higher

H

values

but

J

values

are

likely

to

drop

as

in

fact

our

results

for

indicate

This

raises

the

question

where

the

balance

between

H

and

J

is

optimal

as

more

categories

require

more

extensive

subsequent

studies

to

derive

utility

functions

for

the

associated

classification

system

How

the

Shannon

indices

will

behave

in

a

different

population

such

as

patient

populations

remains

to

be

investigated

So

far

Shannon

's

indices

proved

to

be

useful

in

showing

weaknesses

of

level

gradings

used

in

and

and

offers

leads

for

improvement

establishing

their

practical

psychometric

value

O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

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