Maternity Experiences Survey (MES)

Detailed information for 2006




One Time

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The Maternity Experiences Survey (MES) is the first Canadian survey devoted to pregnancy, labour, birth and postpartum experiences. It is a core project of the Canadian Perinatal Surveillance System of the Public Health Agency of Canada who sponsored this survey.

Data release - November 27, 2007 (A full report on the MES will be available from the Public Health Agency of Canada in October 2008.)


The Maternity Experiences Survey was the first national survey devoted to this topic in Canada. Its purpose was to collect data from recent mothers on important perinatal health indicators, such as:
- health and health care during pregnancy
- labour and birth practices as well as an overall evaluation of the experience
- characteristics and health of the newborn, breastfeeding intentions and practice
- mothers' views of their postpartum health and health care
- information mothers had on pregnancy, childbirth and postpartum period
- other factors that may have affected their maternity experiences (e.g., socio-demographic characteristics, reproductive history, stressful events, support).

Survey results will be of interest to maternal and child health researchers, public health professionals, policy makers, women's groups, and professional organisations in the field of maternal and baby's health. The ultimate goal of the survey was to gain information that could help improve the health and well-being of pregnant women, mothers and infants in Canada.

The survey was conducted in the fall of 2006, following the Canadian Census of Population. The survey's sample was selected using demographic information collected during the census. The target population was defined as women who:

- gave birth between the 15th of February and the 15th of May 2006 (provinces) or between the 1st of November 2005 and the 1st of February 2006 (territories);
- had a single birth;
- were at least 15 years of age at the time of baby's birth;
- whose baby was born in Canada and lived with the mother at least one night per month.
- Mothers who lived on First Nations reserves and in collective dwellings were excluded.

Of the estimated 76,500 women who would meet these criteria, the MES sample included 8,542 mothers. The survey's file contains 6,421 records of mothers who responded to the survey and gave Statistics Canada permission to share their responses with the survey sponsor.

The telephone computer-assisted interview lasted about 45 minutes on average; both the respondents and the interviewers found the survey important and interesting.

Reference period: From 12 months before baby's birth to between 5 and 14 months after the birth


  • Health
  • Health care services
  • Pregnancy and births

Data sources and methodology

Target population

The target population was composed of women who gave birth between February 15 and May 15, 2006 (provinces) and between November 1, 2005 and February 1, 2006 (territories) and who had a single birth. The mother had to be at least 15 years old at the time of baby's birth and the baby had to be born and live with the mother in Canada. Mothers living on First Nations reserves and in collective dwellings were excluded.

The survey population differs slightly from the target population due to some degree of undercoverage inherited from the 2006 Census, which was used to construct the MES frame.

Instrument design

The questionnaire was designed by the Maternity Experiences Study Group at the Maternal Health Section of the Public Health Agency of Canada. It was then somewhat modified to comply with standards and practices of Statistics Canada during survey development work carried out by the MES team that included representatives of the Public Health Agency.

A pilot of the survey was conducted in November and December 2005 by Statistics Canada. The sample of recent mothers consisted of 210 women residing in all the provinces and territories. The telephone, computer assisted interviews were observed by the MES team members. The interviewers provided their comments and an evaluation of the CATI application and the questionnaire. The results of the pilot and the comments received were used to make revisions to the instrument.


This is a sample survey with a cross-sectional design.

MES is a post-censal survey - its frame was constructed from the 2006 Canadian Census of Population. The Census date of birth was used to identify babies born between the target dates, and the relationship variable was used to identify the household member likely to be the mother of the baby.

The MES frame was stratified by province or territory, the mother's age, and in some provinces by whether the mother resided in a CMA, or whether there were other children in the household. The sample allocation to the provinces and territories was a compromise between equal allocation and proportional allocation. Mothers aged less than 20 at the time of birth were oversampled. A simple random sample was selected without replacement within each stratum.

The sample consisted of 8, 542 women.

Data sources

Data collection for this reference period: 2006-10-23 to 2007-01-31

Responding to this survey is voluntary.

Data are collected directly from survey respondents.

In the provinces, the method of data-collection was a computer assisted telephone interview (CATI), while in the territories if a telephone interview was not feasible, a personal interview with a paper version of the questionnaire was offered where possible. Close to 30 interviews were conducted in person.

The sample file sent to collection contained the baby's name and the mother's name (the name of the household member identified as most likely to be the mother of the baby). When contact was made with the household, the interviewer asked to speak to the person identified as the mother of the baby. The next two modules (SRC, VSB) of the CATI application were used to determine whether the mother-baby pair were in-scope for MES. The SRC module had questions regarding the presence of the baby in the household (at least one night per month), the name of the mother and her presence in the household. If the wrong person was identified as the mother on the sample file, the interviewer asked to speak to the mother. The VSB module asked questions about the mother and baby's date of birth, verified that the mother was the birth mother, confirmed that the baby was born in Canada, and confirmed that the baby was a single birth.

The computer application had special features to maximize the success rate of the attempts to reach respondents. The 25 calls allowed per case were distributed between working days and the weekend and between mornings, afternoon and evenings taking into consideration the schedules of mothers of young babies.

The average interview time for fully completed interviews was about 45 minutes.

View the Questionnaire(s) and reporting guide(s) .

Error detection

The computer application for the MES controlled the flow of the questions and included built-in consistency edits as well as minimum and maximum values for the majority of questions where such edits could be performed. Still, there were some records with flow errors, impossible values or inconsistent answers that required intervention as part of data processing.

The first type of error treated were errors in the questionnaire flow, where questions which did not apply to the respondent (and should therefore not have been answered) were found to contain answers. In this case a computer edit automatically eliminated superfluous data by following the flow of the questionnaire implied by answers to previous questions.

The second type of error treated involved a lack of information in questions which should have been answered. For this type of error, a non-response or "not-stated" code was assigned to the item.


This methodology type does not apply to this survey.


Estimates are produced using weights attached to each record. The weight of a record indicates the number of mothers it represents. The weights were calculated in several steps:

1) An initial weight was calculated based on the probability of selecting the unit in the sample.

2) The weights were adjusted to account for cases with insufficient data to determine whether they were in-scope for the survey. The weighting adjustments were calculated within weighting classes.

3) The weights were adjusted to account for in-scope non-respondents. The weighting adjustments were calculated within weighting classes.

4) Generalized regression (GREG) estimation was used to calibrate the weights and to make them agree with 2006 Census counts for the survey population.

Quality evaluation

Specialists in pregnancy, birth and postpartum fields validated the survey estimates through comparison with existing sources such as vital statistics and other surveys.

Disclosure control

Statistics Canada is prohibited by law from releasing any data that would divulge information obtained under the Statistics Act that relates to any identifiable person, business or organization without the prior knowledge or the consent in writing of that person, business or organization. Various confidentiality rules are applied to all data that are released or published to prevent the publication or disclosure of any information deemed confidential. If necessary, data are suppressed to prevent direct or residual disclosure of identifiable data.

The survey master/share file does not include personal identifiers such as name, address, and telephone number.

Revisions and seasonal adjustment

This methodology type does not apply to this survey.

Data accuracy

While considerable effort is made to ensure high standards throughout all stages of collection and processing, the resulting estimates are inevitably subject to a certain degree of error. These errors can be broken down into two major types: non-sampling and sampling.

About the non-sampling errors:
Considerable time and effort were taken to reduce non-sampling errors in the survey. Quality assurance measures were implemented at each step of the data collection and processing cycle to monitor the quality of the data. These measures include the use of highly skilled interviewers, extensive training of interviewers with respect to the survey procedures and questionnaire, observation of interviewers to detect problems of questionnaire design or misunderstanding of instructions, and edit quality checks to verify the processing logic.

The response rate for the MES was 78%.

About the sampling errors:
Sampling error occurs because population estimates are derived from a sample of the population rather than the entire population. Sampling error depends on factors such as sample size, sampling design, and the method of estimation.

The basis for measuring the potential size of sampling errors is the standard error of the estimates derived from survey results. Because of the large variety of estimates that can be produced from a survey, the standard error of an estimate is usually expressed relative to the estimate to which it pertains. This resulting measure, known as the coefficient of variation (CV) of an estimate, is obtained by dividing the standard error of the estimate by the estimate itself and is expressed as a percentage of the estimate.

The quality of the estimates was assessed using estimates of their coefficient of variation. The CVs were calculated using bootstrap weights which take the sample design into account.

Please refer to Chapter 8.0 (Data Quality) of the User Guide for detailed information.


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