Head Injury
Description
Specific Information: Head Injury by month
The head injury calendar reflects a monthly plotting of the months in which the subject had a head injury that resulted in loss of consciousness and/or required medical treatment (e.g. stitches). These items were developed for the study based on a consultation with two neuropsychologists (Lisa Marrow, University of Pittsburgh School of Medicine and Charles Nelson, University of Minnesota). A recall level item establishes the presence of a brain injury (e.g., had a head injury that resulted in the loss of consciousness). If the subject indicated he/she sustained a head injury during the recall period, he/she is then asked to indicate the month(s) of the recall period during which the injury occurred. This data can be used in conjunction with the recall level summary variables that are available in the codebook section "Head Injury" under "Measures".
Descriptive Information: Monthly Data Characterizing the Recall Period
As a standard practice, the specific calendar information will be accompanied by four variables which describe the recall period. This information is important for the user to consider when attempting to use data characterizing the recall period (e.g., measures) in conjunction with the monthly-level calendar data. In addition, this information is useful if the user is viewing events from a developmental perspective. These variables include:
- The actual number of days in each month that is represented in the calendar data.
- The calendar month and year mapped to the recall month (e.g., if S1M04 covers February 2003, the 'number of days' value for that month will be 28, and the calendar month associated with S1M04 will be 02/2003, "RealDate").
- The subject's age at each month of the recall period, available in two forms: 1) the subject's age truncated to a whole number, and 2) the age as a continuous variable. (The subject age at the time of the interview is available in the "Demographics" codebook, available under "Measures").
- A marker indicating whether each month of the recall period is a community or institution month, where an institution month is defined as a month where the subject spent eight or more days across the following type of out of community placements: drug/alcohol facility, psychiatric hospital or unit, jail or prison, detention, YDC or ADJC, contracted residential treatment (general), and contracted residential treatment (mental health). These setting types are described in detail in the "Out of Community Placements" codebook, available under "Calendars".
In addition, each dataset includes five variables which describe basic information related to the interview. These are explained in full detail in the "Interview Information" section under "Measures". These variables include the completion status of the interview, the date of the interview, version number in which the interview was conducted, the number of months in the recall period, and the number of days in the recall period.
General Information: Use of monthly life calendar data
Data regarding the participant's self-reported head injuries is captured using a monthly life-calendar approach (Belli, 1998; Caspi, Moffitt, Thornton, & Freedman, 1996), where the research participant is provided with a visual calendar that contextualizes the recall of research data by anchoring information to salient events. Specifically, individuals are first asked to recount salient events which occurred in the recall period (e.g. birthdays, deaths) and this information remains visible to the participant as an anchor point for the timing of events in each of several life calendar domains. This approach thus creates an integrated view of activities in all of the domains examined, has firm roots in the science of how people remember events and life situations (Bradburn, Rips, and Shevell, 1987; Belli, 1998), and capitalizes on these processes to generate accounts of past events. On a practical level, it provides researchers with a richer set of data points. Instead of simply getting a summary measure of life changes over an extended recall period, the monthly life-calendar places these changes at specific points in time, opening up the possibility of examining sequences of events and potential causal mechanisms within individuals (Fals-Stewart, 2003; Mulvey, et al., 2006).
General Information: Conversion of data to linear months
The monthly Pathways data, in its raw form, is not suited for some kinds of analytic approaches (e.g., trajectory analysis). Each time point interview allows for a maximum of eight or 14 months in the recall period, depending on the follow-up wave (eight months was the maximum for time points 6-36 and 14 was the maximum for time points 48-84). This means that there is a corresponding variable in the dataset reflecting events occurring in each of those months through a maximum of 14 months (the outer limit of any of the possible months covered). If however, the recall period did not include the maximum number of months (as is most often the case), there will be variables with no data. For example, subject 1 has a recall period of five months for follow-up 12 so this means he/she will have data in five monthly variables but not in the remaining nine. Subject 2, has seven months in the recall period for follow-up 12 so he/she will have data in all but seven of the monthly variables. The recall length is set by programming code based on the current date in relationship to the date of the previous interview (see "Interview Information" under Measures for a more detailed description of how the length of the recall period is determined). However, the programming code did permit the interviewer to "reset" by hand the length of the recall period. This was done infrequently, but in some instances it created a situation where we obtained two reports of the same month. For example, follow-up 6 covered months January to June and the interviewer resets the follow-up 12 recall period to start with June (leading to two different reports for the month of June).
The "linear months" data set-up corrects these two situations. The "linear months" data reformats the variables so that each variable is a sequential representation of life event data for each month of the research participant's life from the baseline interview forward. In this format, variables that were place-markers for months not covered in the recall period are eliminated and situations where there were two reports for the same month are corrected. Thus, "linear month 8" actually represents eight calendar months from the baseline and "linear month 16" is actually 16 months past the baseline interview.
A specific list of variables available in the linear format is provided below. Also provided is a "map" to link the linear month back to the recall period and month in which the information was originally collected. This is important to know when recall-level data is being used in conjunction with the monthly event calendar data.
Data Issues
- The follow06 through follow36 timepoints allow for a maximum of eight months in the recall period, while follow48 and later will have a maximum of 14. Note that while variables for months 9 through 14 are included in the datasets for follow06 through follow36, these are essentially place markers and in no instance will any case have data for these months until the follow48 period (see description above).
Items available regarding head injury
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Description of Variable | Variable Name | Version Changes | |
---|---|---|---|
By month | |||
Head Injury | |||
Whether a head injury occurred where the subject lost consciousness and/or required medical attention | S#HeadInj_Injured_M## | ||
Data characterizing the recall period | |||
Subject age at each month (truncated) | S#SubjAge_M## | ||
Subject age at each month (continuous) | S#CTSubjAge_M## | ||
Community vs. Institution month marker | S#CommunityMonth_M## | ||
Number of days covered in each month | S#NDays## | ||
Calendar month linked to each s#m# | S#RealDate## | ||
By linear month | |||
Head Injury | |||
Whether a head injury occurred where the subject lost consciousness and/or required medical attention | L##HeadInj_Injured_M## | ||
Data characterizing the recall period | |||
Subject age at each month (truncated) | L##SubjAge | ||
Subject age at each month (continuous) | L##CTSubjAge | ||
Community vs. Institution month marker | L##CommunityMonth | ||
Number of days covered in each month | L##NDays | ||
Calendar month linked to each s#m# | L##RealDate | ||
Recall period month (s#m#) mapped to linear month number ## | L##TpMo | ||
Additional sections supplement this calendar. Refer to the codebook section for each listing for more information | |||
Interview Information -- contains variables that describe basic information related to the interview, such as interview completion status, interview date, version, and number of months and days covered by the recall period. This can be found under the "Interview Information" section of the Measures codebook. | |||
Head Injury -- contains recall level information establishing the presence of a brain injury (e.g., had a head injury that resulted in the loss of consciousness). This can be found under the "Head Injury" measure of the codebook. |
References
- Caspi, A., Moffitt, T., Thornton, A., Friedman, D., Amell, J., Harrington, H., et al. (1996). The Life History Calendar: A research and clinical assessment method for collecting retrospective event-history data. International Journal of Methods in Psychiatric Research, John Wiley & Sons, Inc., US, 6(2), 101-114.
- Belli, R.F. (1998). The structure of autobiographical memory and the event history calendar: Potential improvements in the quality of retrospective reports in surveys. Memory, 6(4), 383-406
- Head injury items developed for the study based on consultation with Lisa Morrow (WPIC) and Charles Nelson (University of Minnesota).