Missing Values in the MDS


Values that are "missing" in the Minimum Data Set (MDS) nursing home assessment can be represented by several different symbols. While all of these symbols represent that a value is "missing," the specific symbol indicates the specific reason why the value is missing.
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These missing value codes are dash ('-'), space (' '), asterisk ('*'), ampersand ('&') and caret ('^'). When a field is 2 or more characters long, then the field is filled to its length with the missing value code.  For example, a 2-character field would contain '**', a 3-character field would contain '***', etc.

Dash ('-') indicates that the assessor addressed the item but was unable to determine a response.

Additional information about a dash for MDS 3.0:

Dashes are used to indicate that an item was not assessed or the information was not available. For example, if a resident is in a facility for only a few days, it may not be possible to complete the entire assessment. In this case, the assessor may indicate for certain items that the item was not assessed. Dashes are allowed on most, but not all, items. When a dash is allowed for an item, it will be listed in the “Item Values” table. A dash must not be submitted for items where the “Item Value” table does not list it as an allowable value; submitting dashes for such items will result in a fatal error. When a dash is allowed for not assessed, a single dash should be submitted for the item regardless of the item’s normal length.

Space (' ') indicates that the item was skipped and is not relevant on this MDS assessment or tracking form.  For example, if b1 = 1 (resident comatose), then B2a and B2b (memory items) are irrelevant, cannot be assessed, and will be space filled.  See the MDS data specifications to determine the skip patterns for MDS records.

Asterisk ('*') indicates that the item was not active on this assessment or tracking form (e.g., item not present on this quarterly assessment) or was out-of-range on submission.  For assessments submitted after 4/28/2000, records will be rejected if there is an out-of-range value on most fields (only exceptions are a few computed fields--Rec_type and the RUGs fields T3mdrc and T3state).  For records submitted after 4/28/2000, an '*' will always indicate an inactive item.  For records submitted before 4/28/2000, an '*' indicates the item was inactive or out-of range.

Ampersand ('&') indicates that the item was inactive.  This is an old coding convention that should not occur in records submitted from the end of April 1999 forward.

Caret ('^') is used in the submission file to indicate that an item has been left blank due to a skip pattern or, for certain text items, that the item has been left blank by the assessor. If an item is active for given type of assessment but has been skipped because it is in a skip pattern, then the XML tags for the item must be included in the XML file and a single caret must be submitted as the value between the element’s tags.