Table 3 Estimated item parameters for a subsample (n = 28) of Read stroke codes retained for the IRT analyses.

Thrombosis cavernous sinus

2.785

0.772

4.468

0.490

2136.3

Thrombosis transverse sinus

2.632

0.677

4.677

0.529

1934.8

Thrombosis of CNS venous sinuses NOS

2.077

0.635

5.717

1.007

816.9

CI due to cerebral venous thrombosis, nonpyogenic

1.642

0.446

5.998

1.162

653.7

Cortical haemorrhage

1.824

0.635

6.079

1.279

607.5

Phlebitis and thrombophlebitis of intracranial sinuses

1.813

0.648

6.265

1.458

518.2

Thrombosis lateral sinus

1.732

0.594

6.307

1.478

507.4

Vertebral artery occlusion

1.097

0.522

8.490

3.500

44.7

Subarachnoid haemorrhage from anterior

1.054

0.511

8.793

3.737

34.5

Brainstem infarction NOS

1.051

0.509

8.816

3.754

33.2

CI due to embolism of precerebral arteries

0.905

0.413

8.956

3.677

29.4

Pure motor lacunar syndrome

0.883

0.401

9.059

3.720

10.7

Ruptured berry aneurysm

0.797

0.341

9.177

3.595

7.7

Brainstem infarction

0.783

0.334

9.242

3.613

7.0

Thrombophlebitis of CNS venous sinuses

0.836

0.387

10.002

4.269

4.1

Extradural haemorrhage - nontraumatic

0.843

0.392

10.006

4.283

4.1

Subacute confusional state of cerebrovascular origin

0.811

0.371

10.007

4.227

3.9

Subarachnoid haemorrhage NOS

0.805

0.367

10.012

4.219

3.8

Left sided intracerebral haemorrhage, unspecified

0.850

0.396

10.013

4.299

4.1

Pontine haemorrhage

0.794

0.360

10.024

4.205

3.7

Intracerebral haemorrhage, intraventricular

0.774

0.347

10.059

4.185

3.4

CI due to unspecified occlus of precerbral arteries

0.880

0.417

10.079

4.387

4.0

Infarction of basal ganglia

0.760

0.339

10.091

4.174

3.2

Pure sensory lacunar syndrome

0.897

0.429

10.153

4.456

3.8

Subarachnoid haemorrhage from middle artery

0.735

0.323

10.163

4.161

2.8

Sequelae of stroke not specified

0.706

0.305

10.266

4.154

2.3

Occlusion and stenosis of middle cerebral artery

0.948

0.465

10.696

4.835

5.7

Occlusion and stenosis of posterior cerebral artery

0.972

0.483

11.582

5.384

0.0