Feature variables considered in the correlation tests
| Variables | Description | Range of values | In regression analysis | Proposed effect on schedule variations | Sources of complexity | |
|---|---|---|---|---|---|---|
| Categorical | Item | Unique component number | 4,977 items | |||
| Item group | Internally defined item categories | Nominal categories | ||||
| Supplier | Name of the supplier organization | Nominal categories | ||||
| Material receiving address | Plants that receive and use the item | 14 addresses | ||||
| Scheduled demand date (3 variables) | A combined year and week number | 76 weeks: between 2017 (week 31) and 2018 (week 52) | ||||
| Year | Two years: 2017 and 2018 | |||||
| Week number | 52 weeks | |||||
| Transport lead time in days | The standard time required for delivering items from the supplier to the receiving address | 13 categories: 0–9, 11, 13, 41, 45, 46 | X | Contingent cause | Insufficient buffering of time, process design | |
| Pick-up frequency in times per week | The number of days per week when picking up material from the supplier is possible | Five categories: 1–3, 5, 6 | X | Independent moderator | Scale dynamics, process design | |
| Phase-in/-out week | Does the schedule belong to the fixed phase-in/out weeks (two weeks per year)? | Two states: yes, no | ||||
| Shifts in scheduled volumes from or to zero | Does the scheduled volume change from any value to zero or vice versa? | Two states: yes, no | ||||
| Holiday week | Weeks per year when the plants are closed | Two states: yes, no | ||||
| Car Model A | Do the items exist in the model’s BOM? | Two states: yes, no | X | Independent cause | Scope dynamics, process design | |
| Car Model B | Two states: yes, no | X | Independent cause | Scope dynamics, process design | ||
| Car Model C | Two states: yes, no | X | Independent cause | Scope dynamics, process design | ||
| Car Model D | Two states: yes, no | X | Independent cause | Scope dynamics, process design | ||
| Car Model E | Two states: yes, no | X | Independent cause | Scope dynamics, process design | ||
| Car Model F | Two states: yes, no | X | Independent cause | Scope dynamics, process design | ||
| Numerical | Forecasted volume | Forecasted volume X weeks before the delivery date, X = {2, 4, 8, 12} | ≥0 | X | Contingent cause | Variations in timing, process context |
| Unit load per week | Unit load divided by the average weekly demand or reference volume | ≥0 | X | Contingent moderator | Scale dynamics, process design | |
| Aggregated production deviation | Number of cars behind or ahead of actual demand | (−) behind (+) ahead | X | Contingent cause | Variations in quality, process context | |
| Item’s order life cycle ratio | The number of weeks from the first delivery date in the dataset to present over the number of weeks from the first delivery date to the last planned date on the horizon | 0–1 | X | Contingent cause | Scope dynamics, process design | |
| Take rate at the plant level | Percentage of manufactured cars at a plant in which the item is used | 0–1 | X | Contingent cause | Scope dynamics, process design | |
| Variables | Description | Range of values | In regression analysis | Proposed effect on schedule variations | Sources of complexity | |
|---|---|---|---|---|---|---|
| Categorical | Item | Unique component number | 4,977 items | |||
| Item group | Internally defined item categories | Nominal categories | ||||
| Supplier | Name of the supplier organization | Nominal categories | ||||
| Material receiving address | Plants that receive and use the item | 14 addresses | ||||
| Scheduled demand date (3 variables) | A combined year and week number | 76 weeks: between 2017 (week 31) and 2018 (week 52) | ||||
| Year | Two years: 2017 and 2018 | |||||
| Week number | 52 weeks | |||||
| Transport lead time in days | The standard time required for delivering items from the supplier to the receiving address | 13 categories: 0–9, 11, 13, 41, 45, 46 | X | Contingent cause | Insufficient buffering of time, process design | |
| Pick-up frequency in times per week | The number of days per week when picking up material from the supplier is possible | Five categories: 1–3, 5, 6 | X | Independent moderator | Scale dynamics, process design | |
| Phase-in/-out week | Does the schedule belong to the fixed phase-in/out weeks (two weeks per year)? | Two states: yes, no | ||||
| Shifts in scheduled volumes from or to zero | Does the scheduled volume change from any value to zero or vice versa? | Two states: yes, no | ||||
| Holiday week | Weeks per year when the plants are closed | Two states: yes, no | ||||
| Car Model A | Do the items exist in the model’s BOM? | Two states: yes, no | X | Independent cause | Scope dynamics, process design | |
| Car Model B | Two states: yes, no | X | Independent cause | Scope dynamics, process design | ||
| Car Model C | Two states: yes, no | X | Independent cause | Scope dynamics, process design | ||
| Car Model D | Two states: yes, no | X | Independent cause | Scope dynamics, process design | ||
| Car Model E | Two states: yes, no | X | Independent cause | Scope dynamics, process design | ||
| Car Model F | Two states: yes, no | X | Independent cause | Scope dynamics, process design | ||
| Numerical | Forecasted volume | Forecasted volume X weeks before the delivery date, X = {2, 4, 8, 12} | ≥0 | X | Contingent cause | Variations in timing, process context |
| Unit load per week | Unit load divided by the average weekly demand or reference volume | ≥0 | X | Contingent moderator | Scale dynamics, process design | |
| Aggregated production deviation | Number of cars behind or ahead of actual demand | (−) behind (+) ahead | X | Contingent cause | Variations in quality, process context | |
| Item’s order life cycle ratio | The number of weeks from the first delivery date in the dataset to present over the number of weeks from the first delivery date to the last planned date on the horizon | 0–1 | X | Contingent cause | Scope dynamics, process design | |
| Take rate at the plant level | Percentage of manufactured cars at a plant in which the item is used | 0–1 | X | Contingent cause | Scope dynamics, process design | |
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