Adjustment of Truncation Effect in First Birth Interval using Current Status Data Technique

Sachin  Kumar; Anup  Kumar; Amit Kumar  Misra; Jai  Kishun; Uttam  Singh

doi:10.18502/jbe.v10i2.17644

Sachin Kumar Department of Biostatistics and Health Informatics Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India.
Anup Kumar Department of Biostatistics and Health Informatics Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India.
Amit Kumar Misra Department of Statistics, Babasaheb Bhimrao Ambedkar University Lucknow, India.
Jai Kishun Department of Biostatistics and Health Informatics Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India.
Uttam Singh Department of Biostatistics and Health Informatics Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India.

DOI: https://doi.org/10.18502/jbe.v10i2.17644

Keywords: Spline smoothing; Truncation effect; Selection bias; Current status data; Ayer method

Abstract

Introduction: Estimating the First Birth Interval (FBI) from cross-sectional data often presents challenges related to truncation effects. These challenges stem from the data’s inability to capture the enough exposure for an event, resulting in potential biases and inaccuracies in FBI estimates. Recognizing and addressing truncation effects is essential for obtaining more precise and meaningful fertility parameter estimates in a cross-sectional survey. This study seeks to mitigate truncation effects in the estimation of the FBI by utilizing the Current Status Data technique. This approach focuses on women with specific marital durations, providing a means to counteract the bias caused by truncation and thereby yielding more accurate and reliable FBI estimates.

Methods: Data from the National Family Health Survey (NFHS-IV) are employed for this study. The Current Status Data Technique is applied to the dataset, considering exclusively those women with marital durations less than 120 months. This methodology enables the adjustment of truncation effects and facilitates a more precise estimation of the FBI. Statistical analysis is conducted to determine the FBI distribution and ascertain the necessary sample size.

Results: The estimated First Birth Interval (FBI) without accounting for truncation is 27.85 months, while the estimate considering truncation is 31.70 months. When applying the Current Status Data technique, the estimated FBI is 30.70 months. To obtain reliable estimates of the FBI using Current Status techniques, a minimum sample size of over 5,000 observations is necessary.

Conclusion: The truncation effect in FBI is addressed, and some non-parametric adjustments are used for estimating the duration of FBI. The Current Status Data technique emerges as a valuable tool for mitigating these effects and enhancing the precision of FBI estimates. This research contributes to an improved understanding of fertility dynamics and provides valuable insights for future studies on the First Birth Interva