Careers of Doctorate Holders survey (CDH)

What does the survey comprise?

Purpose

The objective is to gather information about how PhD graduates experienced their doctoral period and about their careers after obtaining their doctorate.

Target population

Individuals who have obtained their PhD at a university affiliated with the Universities of the Netherlands (UNL) since the academic year 1990/’91, who were under the age of 70 at the time of the survey, and who were residing in the Netherlands according to the Basic Registration of Persons (BRP) at that time.

Statistical unit

Individuals.

Date/year survey started

The Careers of Doctorate Holders survey has been conducted since 2010. The StatLine tables are based on data from the 2019 edition.

Frequency

Approximately every 5 years.

Publication strategy

The figures are final.

How is the survey conducted?

Survey type

Sample survey. The sample frame is based on information provided by universities about PhDs awarded each year. The sample frame consists of individuals who were linked to the Basic Registration of Persons (BRP). In 2010 and 2014, the sample frame was approached integrally. Since 2019, it has been a sample of individuals.

Survey method

The Careers of Doctorate Holders survey is conducted in March and April. Sample participants receive an invitation letter inviting them to complete an online questionnaire (CAWI – Computer Assisted Web Interviewing). A maximum of two reminder letters are sent. The invitation letter, reminder letters, and the questionnaire are only available in Dutch.

Respondents

The respondents are PhD graduates.

Sample size

The sample sizes in 2019 and 2025 were approximately 20,000 PhD graduates. Of these, more than 9,700 participated in the 2025 survey (49.6%) and over 11,100 in 2025 (55.7%).

Checking and correction methods

Standard plausibility checks for internal consistency and completeness were conducted.

Weighting

A two-step weighting method was applied. The weighting method corrects for under- and overrepresentation of certain groups in the response.
In the first step, correction is made for selectivity in the response. This involves characteristics such as gender, age, marital status, income, origin, place of residence (region), university, and year of obtaining the PhD. In this step, the sample frame is also adjusted. In the second step, correction is made for the fact that a portion of the target population did not link to the Basic Registration of Persons (BRP).

Quality of the results

Accuracy

The results of the Careers of Doctorate Holders survey are subject to random fluctuations because the survey is based on a sample. If the number of sample participants for a specific target population is less than 100, no results are presented in the StatLine tables, and these figures are replaced with a dot (.). For all figures not only the value is published, but also the confidence interval. The actual value is 95% likely to lie within this interval. The size of the confidence interval is partly determined by the sample size. Larger samples mean smaller confidence intervals and more accurate estimates.

Quality strategy

All data is checked for plausibility, internal consistency and completeness.