 
Construct validity

Construct responsiveness



Correlations^{#}
 
Correlations


Hypothesis*

Expected

Observed

Hypothesis

Expected

Observed


ODI_{sum. score}

PEIBP_{sum. score}

a

< − 0.5

− 0.5407

a

< − 0.5

− 0.5552

BIPQ_{sum. score}

PEIBP_{sum. score}

a

< − 0.5

− 0.5808

a

< − 0.5

− 0.5375

BIPQ_{q.3}

PEIBP_{sum. score}

b

> 0.5

0.4341

b

> 0.5

0.5484

BIPQ_{q.7}

PEIBP_{q. 2}

b

> 0.5

0.5962

b

> 0.5

0.4635

FABQ_{phys. activity}

PEIBP_{sum. score}

c

− 0.3 to − 0.5

− 0.3043

c

− 0.3 to − 0.5

− 0.4301

SF36 Mental health

PEIBP_{sum. score}

d

0.3 to 0.5

0.4986

d

0.3 to 0.5

0.4069

Educational level

PEIBP_{sum. score}

e

≤ 0.3

0.1259
   
Number of previous episodes of LBP

PEIBP_{sum. score}

f

≥ − 0.3

− 0.0365
   
 ODI = Oswestry Disability Index; sum. score = summary score; PEIBP = Patient Enablement Instrument for Back Pain; BIPQ = Brief Illness Perception Questionnaire; q = question; FABQ_{phys.activity} = Fear Avoidance Belief Questionnaire, the physical activity sub scale; SF36 = Short Form 36
 ^{*}Hypothesis: (a) Scales are expected to measure the same construct. The correlation is expected to be negative and high (< 0.5). (b) Scales are expected to measure the same construct. The correlation is expected to be positive and high (> 0.5). (c) Scales are related but do not measure the same construct. The correlation is expected to be negative and moderate (0.3 to 0.5). (d) Scales are related but do not measure the same construct. The correlation is expected to be positive and moderate (0.3 to 0.5). (e) Scales are expected not to measure the same construct. The correlation is expected to be positive and low (≤ 0.3). (f) Scales are expected not to measure the same construct. The correlation is expected to be negative and low (≥ 0.3)
 Bold numbers are positive hypotheses and plain numbers are negative hypotheses
 ^{#}Spearman’s rank correlation coefficient