How to Populate Variables

• Variables subject to controlled terminology will be populated with the exact value for the controlled term, including term casing.
• Otherwise, text data will be represented in upper case (e.g., NEGATIVE).

• For variables where the response is "Yes" or "No", both "Y" and "N" will be   
• Variables where the response is "Yes" or "No" ("Y" or "N") should normally be populated for both "Y" and "N" responses. This eliminates confusion regarding whether a blank response indicates "N" or is a missing value. However, some variables are collected or derived in a manner that allows only 1 response, such as when a single checkbox indicates "Yes". In situations such as these, where it is unambiguous to populate only the response of interest, it is permissible to populate only 1 value ("Y" or "N") and leave the alternate value blank. An example of when it would be acceptable to use only a value of "Y" would be for Last Observation Before Exposure Flag (--LOBXFL) variables, where "N" is not necessary to indicate that a value is not the last observation before exposure.

--SEQ

• Values in --SEQ will uniquely identify a record for a given USUBJID or SPTOBID within a domain.
• Conventions for establishing and maintaining --SEQ values are applicant-defined. Values may or may not be sequential depending on data processes and sources.

--REFID

• Values for --REFID are sponsor-defined and can be any alphanumeric strings the sponsor chooses, consistent with their internal practices.

• In general observation class domains, --STAT will be populated with "NOT DONE" when data are not collected for the topic of the observation.

• Variable --ORRES:
  • Will be populated with the result of the measurement or finding as originally collected or received (using controlled terminology where applicable).  
• --ORRES is an expected variable and should always be populated, except (1) when --STAT = "NOT DONE" (because there is no result for such a record) or (2) for derived records.

Note: Records with --DRVFL = "Y" may combine data collected at more than 1 visit. In such cases, sponsors must define the value for VISITNUM, addressing the correct temporal sequence. If a new record is derived for a dataset by the sponsor or their agent (e.g., a CRO), then that new record should be flagged as derived.
For example, in electrocardiogram (ECG) data, if a corrected QT interval value derived in-house by the sponsor were represented in an SDTM record, then EGDRVFL would be "Y". If a corrected QT interval value was received from a vendor or was produced by the ECG machine, the derived flag would be null.

When --ORRES is populated, --STRESC must also be populated, regardless of whether the data values are character or numeric. The variable --STRESC is populated either by the conversion of values in --ORRES to values with standard units, or by the assignment of the value of --ORRES, as in the Physical Examination (PE) domain, where --STRESC could contain a dictionary-derived term. A further step is necessary when --STRESC contains numeric values. These are converted to numeric type and written to --STRESN. Because --STRESC may contain a mixture of numeric and character values, --STRESN may contain null values, as shown in the following figure.

Figure. Original to Standardized Results

When the original measurement or finding is a selection from a defined codelist, in general, the --ORRES and --STRESC variables contain results in decoded format (i.e., the textual interpretation of whichever code was selected from the codelist). In some cases where the code values in the codelist are statistically meaningful standardized values or scores, which are defined by sponsors or by valid methodologies such as SF36 questionnaires, the --ORRES variables will contain the decoded format, whereas the --STRESC variables as well as the --STRESN variables will contain the standardized values or scores.

Occasionally data that are intended to be numeric are collected with characters attached that cause the character-to-numeric conversion to fail. For example, numeric cell counts in the source data may be specified with a greater than (>) or less than (<) sign attached (e.g., >10,000, <1). In these cases, the value with the greater than (>) or less than (<) sign attached should be moved to the --STRESC variable, and --STRESN should be null. The rules for modifying the value for analysis purposes should be defined in the analysis plan and a numeric value should only be imputed in the ADaM datasets. If the value in --STRESC has different units, the greater than (>) or less than (<) sign should be maintained. See Example 1, Rows 11 and 12