For the following in-house workshop we use invented, fully observed lists with pre-cleared units. They do not represent any real region in Austria or Germany. For real analyses, data access, rights, assignment and data capture rules must be clarified separately. No external portal is being scraped.
Two weekly snapshots with the same ending
- Quiet model week – Inventory at the start: 10; Newly added to the model: 1; Removed from the model inventory: 1; Inventory at the end: 10
- Eventful model week – Inventory at the start: 10; Newly added to the model: 8; Removed from the model inventory: 8; Inventory at the end: 10
The calculation is in each case starting inventory plus additions minus removals. It is deliberately defined completely here. In both cases ten entries remain. However, the number of different entries that were at some point part of the list is different: eleven in the first case, eighteen in the second, provided the new model identifiers were not previously included.
Even this small example refutes the conclusion that identical end inventories automatically mean no movement. It does not yet say why entries changed. The causes are intentionally not invented in the workshop.
An exchange log alongside the snapshot
The fictional editorial team therefore maintains two views. The snapshot shows what is recorded at the specified point in time. The exchange log records the additions and removals observed during the defined period. Each specification uses the same agreed unit.
For real data, it must first be checked whether the required events were actually observed. Two individual screenshots at the beginning and end may not contain everything that happened in between. No complete weekly flow is claimed from them. An entry could have appeared and then disappeared again in the interim without being included in either of the two snapshots.
Such observational limits belong in the description. A small, reliably delimited statement is more useful than a large, unproven quantity model.
Removal initially remains only removal from one’s own recording
The word “removed” in the model merely means that the entry no longer belongs to the defined inventory. It does not confirm a sale or a letting. Reservation, withdrawal, changed recording or unknown reasons are not added without evidence.
If there is an actually confirmed status information in one’s own authorised inventory, it can be assigned separately. If it is missing, the cause remains unknown. A pretty graphic labelled “sold” would not be a substitute for this information.
The same applies to additions. “Added to our series for the first time” is a more precise statement than “brand new on the entire market” when the complete prior history is not known. The editorial team chooses the wording according to its actual observation scope.
The delimitation must remain stable during the week
In the next thought experiment the office expands its own area. Suddenly the list contains more entries. That would not be a clean proof of an actual increase in supply in the old area. The recording has been changed.
Before the report, therefore, area, property type, counting unit and observation rule for the compared inventories are placed side by side. Changes are visibly marked. Either a suitably delimited comparison is created or the break is explicitly described.
Recurring entries also require a treatment defined in advance. The workshop does not create a new identity rule, but requires a confirmed basis. An uncertain assignment is not retrofitted just so that the exchange equation yields the desired value.
What claim the graphic may carry
For the quiet model week the editorial team can say: “The closing inventory remained the same; an entry was replaced in the fully defined model series.” For the second week it names the higher turnover with the same closing inventory. A cause or success rate is not claimed.
If an actual analysis comprises only snapshots, the caption is correspondingly narrower. The editorial team describes the observed inventories and names the missing intermediate observation. It does not calculate an allegedly precise market velocity from incomplete events.
The result is a more factual idea of supply. Inventory describes what is recorded at one point in time. Movement describes the changes observed over the period. Confirmed brokerage would be a separate piece of information. Whoever separates these three levels must not derive an unsubstantiated market story from two identical sums.