Table 2  S-FHAI item statistics in order of difficulty (from hardest to easiest)

Item number

Abbreviated item

Measure

SE

MnSq

Zstd

MnSq

Zstd

22

Pain in the toes

2.01

0.07

1.14

1.17

1.93

4.47

25

Pain in the ankle

1.72

0.06

1.06

0.70

1.33

2.67

23

Pain in the sole of the foot

1.69

0.06

0.98

-0.20

1.14

1.22

6

Blisters

-2.41

0.23

1.00

0.09

1.13

0.59

24

Pain in the heel

1.81

0.06

0.92

-0.77

1.13

0.85

15

Fungal infection in the nail

-2.95

0.30

1.02

0.15

1.12

0.48

20

High arch

-1.83

0.18

1.05

0.38

1.11

0.67

9

Burning feet

-0.61

0.12

1.00

-0.03

1.07

0.85

5

Verruca

-2.08

0.20

1.00

0.04

1.06

0.35

21

Foot pain

1.41

0.11

1.05

1.33

1.04

0.86

16

Hallux valgus

-0.92

0.13

1.01

0.10

1.03

0.31

19

Low arch

-0.36

0.11

1.01

0.26

1.03

0.47

1

Maceration

3.04

0.17

0.99

-0.03

1.02

0.20

10

Cold feet

0.62

0.10

1.01

0.46

1.02

0.75

7

Oedema

0.28

0.10

0.99

-0.19

1.01

0.37

11

Muscle cramps

0.60

0.10

1.00

-0.16

1.01

0.36

8

Sweating

0.50

0.10

0.98

-0.68

0.98

-0.71

17

Taylor’s bunion

-1.40

0.16

0.98

-0.14

0.93

-0.53

18

Hammer toes

-1.79

0.18

0.98

-0.08

0.92

0.46

3

Fissures

0.41

0.10

0.96

-1.51

0.95

-1.55

12

Ingrown toenails

-1.36

0.15

0.96

-0.29

0.94

-0.43

2

Xerosis

1.98

0.12

0.94

-1.01

0.87

-1.66

4

Corns or callus

0.74

0.10

0.94

-2.68

0.93

-2.65

13

Thickened toenails

-0.30

0.11

0.91

-1.77

0.88

-2.11

13

Discoloured toenails

-0.80

0.13

0.91

-1.14

0.86

-1.60