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Table 1 Overview of the main spare parts classification researches

From: Teleconsultation demand classification and service analysis

References

Classification criteria

Cut-of values of criteria

Classification results

Assumption

[14]

The mean number of lead times between demands

0.5, 0.7, 2.8

Three categories: sporadic, slow-moving, smooth

Poisson demand arrivals

The ‘lumpiness’ of the demand

[15]

The ratio of average inter-order interval and forecast review periods

1.25

Poisson demand arrivals

[16]

Transaction variability

0.1, 0.53, 0.74

Five categories: smooth, irregular, slow-moving, erratic, highly erratic

Demand size variability

Lead-time variability

[13]

The square coefficient of variation of demand sizes, The average inter-demand interval

0.49, 1.32

Four categories: erratic, lumpy, smooth, slow

Bernoulli demand arrivals

[12]

The number of zeroes in the last 13 periods

5–8 for Croston method

Intermittent

2–4 for the SBA method

Non-intermittent

[17]

Frequency

Pareto classification (80%, 95%, 100%)

Three categories: A, B, C

Demand value

[18]

The item first occurred; The average quarterly demand; The average time between demands (quarter); Standard deviation to mean ratio

3, 8; 25; 2; 1.75, 2.50

Lumpy

Outliers must be removed

Erratic

Limited demand

[8]

Correlation; The coefficient of variation in demand volume; The proportion of periods with zero demand; Mean demand volume