2003 SSBF: Methodology Appendix E Screen Reader version ^{♣}

To: John Wolken

From: NORC

CC: Traci Mach

Date: March 11, 2005

2003 SSBF Final Timing Report

The tables on the following page give, in minutes, the mean, median, standard deviation, minimum, and maximum of the times to complete each subsection^{1} of the 2003 SSBF
screener and main interview. For the main interview, these statistics are also reported for the time to complete the interview as a whole.

The summary is based on the screener variable CALC1 and on the main interview variables TCALC1 through TCALC14. These variables contain, in seconds, the times to complete the corresponding sections of the interviews.

Many recorded section times are invalidated because of a break-off during the interview. Missing times and times less than or equal to ten seconds are considered invalid, and it was decided that any section time that is greater than two standard deviations above the mean of the non-missing, greater-than-ten-second section times should be treated as invalid as well.

The statistics for the screener and each main interview subsection are based only on cases that have valid section times, as defined above, for the particular section. The statistics for the main interview as a whole are based only on cases that had valid section times for all fourteen main interview sections.

For the main interview, we began with the 4583 completed cases. For each subsection, invalid cases were then removed and the statistics were calculated using the remaining cases. For the screener, we began with the 13861 cases that had a non-missing section time. The invalid cases were removed and the statistics were calculated using the remaining cases.

A copy of this memo and tables will appear in the Appendix of the methodology report.

Variable |
N with non-missing section time |
N below the lower cutoff^{1} |
N above the upper cutoff^{1} |
N with valid screener timing^{1} |
Mean (minutes) |
Median (minutes) |
Std Dev (minutes) |
Maximum (minutes) |
Minimum (minutes) |
---|---|---|---|---|---|---|---|---|---|

CALC1 | 13861 | 12 | 652 | 13197 | 13.23 | 11.22 | 8.05 | 36.97 | 0.87 |

^{}1Due to the possibility of a break-off and resumption of a screener interview, which would render the interview time meaningless, times below an arbitrary lower cutoff or above an
arbitrary upper cutoff were considered invalid. The lower cutoff for a section time is 11 seconds. The upper cutoff is two standard deviations above the mean of the times above the lower cutoff. The mean, median, standard deviation, maximum and minimum shown here are based on valid section times
only. Return to Table

Subsection |
Variable |
N completed cases |
N below the lower cutoff^{1} |
N above the upper cutoff^{1} |
N with valid section times^{1} |
Mean (minutes) |
Median (minutes) |
Std Dev (minutes) |
Maximum (minutes) |
Minimum (minutes) |
---|---|---|---|---|---|---|---|---|---|---|

A |
TCALC1 | 4583 | 23 | 233 | 4327 | 13.18 | 10.42 | 9.23 | 41.90 | 0.57 |

B and C |
TCALC2 | 4583 | 140 | 118 | 4325 | 3.56 | 2.95 | 1.90 | 10.97 | 0.18 |

D |
TCALC3 | 4583 | 191 | 31 | 4361 | 1.82 | 1.73 | 0.75 | 6.20 | 0.18 |

E |
TCALC4 | 4583 | 164 | 152 | 4267 | 3.74 | 2.88 | 2.67 | 17.95 | 0.18 |

F |
TCALC5 | 4583 | 1731 | 119 | 2733 | 6.98 | 6.02 | 3.95 | 26.00 | 0.18 |

MRL and MRD |
TCALC6 | 4583 | 124 | 231 | 4228 | 12.76 | 5.65 | 14.22 | 53.20 | 0.18 |

G |
TCALC7 | 4583 | 34 | 103 | 4446 | 2.98 | 2.69 | 1.38 | 9.23 | 0.20 |

H |
TCALC8 | 4583 | 107 | 136 | 4340 | 7.03 | 6.13 | 4.08 | 20.40 | 0.18 |

L |
TCALC9 | 4583 | 17 | 133 | 4433 | 2.12 | 2.10 | 1.37 | 6.75 | 0.18 |

M |
TCALC10 | 4583 | 161 | 80 | 4342 | 0.31 | 0.23 | 0.26 | 1.98 | 0.18 |

P |
TCALC11 | 4583 | 6 | 195 | 4382 | 5.56 | 4.62 | 3.04 | 18.88 | 0.28 |

R |
TCALC12 | 4583 | 4 | 118 | 4461 | 3.69 | 3.30 | 1.58 | 10.53 | 0.83 |

S |
TCALC13 | 4583 | 5 | 107 | 4471 | 1.86 | 1.57 | 0.92 | 5.95 | 0.45 |

U and T |
TCALC14 | 4583 | 1 | 168 | 4414 | 4.57 | 4.20 | 1.53 | 10.45 | 1.12 |

Entire Interview^{2} |
4583 | 2097 | 668 | 1817 | 59.11 | 57.55 | 17.72 | 142.03 | 19.95 |

^{1}Due to the possibility of a break-off and resumption of an interview, which would render a section time meaningless, section times below an arbitrary lower cutoff or above an arbitrary
upper cutoff were considered invalid. The lower cutoff for a section time is 11 seconds. The upper cutoff is two standard deviations above the mean of the times above the lower cutoff. The mean, median, standard deviation, maximum and minimum shown here are based on valid section times only. Return to Table

^{2}The timing statistics for the entire interview are based on cases that had a valid time for each of the fourteen sections. Return to Table

Prepared by NORC, Chicago, IL; March 2005.

1. The CATI combined times for subsections B and C, MRL and MRD, and U and T. Return to Text