TABLE 1.
Description of variables utilized in our linear regression model and predicted direction of effect on IFS.
| Direction |
||||||||
|---|---|---|---|---|---|---|---|---|
| Variable | Description | Predictions | N | β | S.E. | Exp. | Obs. | |
| Dependent variable | ||||||||
| Woman’s IFS | Woman’s stated IFS from demographic interviews | Declines with market integration | 305 | 4.621 | 0.137 | |||
| Independent variables | ||||||||
| (1) Socioecology | ||||||||
| Ecological and Socioeconomic | Proximity to town | Resident village was binary coded as 1 = near town, 0 = far from town. Far from town is further divided into three regions based on geographic proximity to the Mission, and whether the village was accessible by road or river. | Women living near town will be more acculturated and have correspondingly lower IFS | 305 | N/A | N/A | N/A | N/A |
| Economic | Women’s schooling index | Principle component of literacy and highest school grade | Women who are better educated and more able to communicate with Bolivian nationals will have smaller IFS | 305 | 0.369* | 0.035 | − | − |
| Literacy | Self-reported reading & writing ability | |||||||
| Highest School Grade | Self-reported highest school grade completed | 305 | 1.175 | 0.097 | − | − | ||
| Spanish fluency | Spanish linguistic skills assessed by interviewer | 305 | 0.580* | 0.039 | − | − | ||
| Social | Surviving sibship Size | Total number of surviving maternal siblings assessed from reproductive histories | Women with more siblings have larger support networks and more alloparents and may consequently have larger IFS. | 299 | 5.920 | 0.162 | + | − |
| (2) Reproductive history | ||||||||
| Age at first birth | Calculated from women’s reproductive histories | In a natural fertility population older women have higher parity and due to post-rationalization bias may have larger IFS | 283 | 18.24 | 0.157 | − | NS | |
| Parity | Total number of living children assessed from reproductive histories | Due to post-rationalization bias women will enlarge their IFS to match their parity. | 305 | 4.80 | 0.199 | + | + | |
| Offspring sex ratio | Sex ratio | Ratio of sons to daughters | Daughters may be a lower cost to maternal energetics and family economics (alloparents & brideprice). Also, sons are highly valued. Women with many daughters may state larger IFS to allow for new sons. | 238 | 1.268 | 0.071 | − | + |
| Sex of oldest surviving child | Sex of the oldest surviving child assessed from reproductive histories (0 = female, 1 = male) | 280 | 0.52** | 0.030 | − | NS | ||
| Total number of marriages at interview | The total number of times a woman had been married assessed from reproductive histories | Women who remarry may have greater autonomy and be less likely to enlarge their IFS to accommodate husbands’ larger IFS. | 305 | 1.20 | 0.030 | − | + | |
| (3) Maternal condition | ||||||||
| Age at interview | A woman’s age at time of interview based on her year of birth | Women who have been reproducing for longer will have larger parity and due to post-rationalization bias have correspondingly higher IFS | 305 | 29.282 | 0.528 | + | + | |
| Age at menarche | Self-reported age started menstruating | Women who have a positive energy balance may be more willing to have large families as they can better afford the cost of reproduction. | 289 | 13.420 | 0.059 | + | + | |
| Maternal energy stores | Principle component of BMI and body fat percentage | |||||||
| BMI | BMI calculated from height & weight data. | 223 | 23.005 | 0.246 | + | NS | ||
| Body fat percentage | Body fat percentage, from bioelectric impedance. | 213 | 24.995 | 0.473 | + | NS | ||
| (4) Husband’s IFS | ||||||||
| Husband’s IFS | Husband’s stated IFS from demographic Interviews | Women, dependent on their husbands’ for socioeconomic support, may inflate their IFS to accommodate their husbands’ larger IFS, and avoid spousal conflict | 216 | 5.520 | 0.245 | + | + | |
| Husband’s capital | Husband’s schooling Index | Principle component of literacy and highest school grade | Men’s IFS are influenced by their education. Better educated men have smaller IFS and encourage their wives to have smaller IFS. | |||||
| Literacy | Self-reported reading & writing ability | 294 | 0.656 | 0.046 | − | NS | ||
| Highest school grade | Self-reported highest school grade completed | 294 | 2.193 | 0.192 | − | NS | ||
| Spanish fluency | Spanish linguistic skills assessed by interviewer | 294 | 0.996 | 0.040 | − | − | ||
A positive correlation is represented by +, a negative correlation by −, N/A is used for Region as it is a categorical variable and must be assessed separately, and NS indicates for Observed Direction where the correlation was non-significant.
For the means * indicates a ranked mean and ** a categorical mean