# _Implementation design and sampling frame_

The SDS implementation design was adjusted to the local context in Vietnam in several ways.

- <u>Respondents. The SDS relied only on job incumbents as respondents and did not use</u> occupation experts. O*NET, in contrast, uses occupational analysts to fill in the skills questionnaire given the abstract nature of skills concepts. However, occupational analysts are not widely available in Vietnam. Given the minimal differences in ratings between analysts and incumbents in the United States and between experts and incumbents in the Indonesia pilot and given the fact that the SDS simplified the questionnaire language, job incumbents were used as respondents (Alatas, Granata, and Posadas 2020).<sup>13</sup> Respondents were selected based on their occupation as stated in previous rounds of the Vietnam Labor Force Survey.

- <u>Number of respondents. The SDS targeted 20 respondents per occupation.</u><sup>14</sup> O*NET’s minimum acceptable sample size per occupation is 10, although this varies widely depending on the questionnaire and respondent type. The SDS aimed to have a balanced sample of respondents from the most economically active areas in the country (Ha Noi, Ho Chi Minh City, Da Nang, Vinh Phuc, and Dong Nai). <mark>In addition, to address the tendency of female underrepresentation in the previous pilots, the SDS designed a sampling frame in which the share of female respondents approximated the share of employment in the occupation at the national level.</mark>

- <u>Data collection strategy. The SDS was a supplement to the December 2021 round of Vietnam’s</u> Labor Force Survey, which is administered by Vietnam’s General Statistics Office, which also oversaw collection of the SDS. This created significant administrative and cost benefits because separate survey collection infrastructure did not need to be created.

- <u>Sample.</u> <mark>Adding the SDS to the Labor Force Survey also permitted the use of the Labor Force Survey’s sampling frame, which includes information about respondents’ occupation at the VSCO 4-digital level. The sampling frame was drawn from the March and September</mark> rounds of the Labor Force Survey. <mark>In total, 543 workers answered the survey. Out of the 30 occupations selected, 15 had a sample size larger than 20 and only 6 smaller than 10.</mark>

- <u>Data collection mode. The SDS survey was conducted in-person and through telephone</u> interviews. Due to the COVID-19 pandemic, 67 percent of interviews were conducted inperson and the remainder through phone calls. These delivery methodologies were preferred to a web-based instrument (as in previous pilots) given the availability of a sampling frame and to improve the survey’s ability to capture lower-skilled occupations.<sup>15</sup>

> 13 However, analysts were preferred for practical considerations (i.e., time, costs, and convenience) (Tsacoumis and Van Iddekinge, 2006) .

> 14 For example, the skills data have a sample of 8 analysts across all occupations, while the tasks data have a range of sample sizes from occupations answered by 3 experts to occupations answered by 247 job incumbents. 15 For cost efficiency in the case of Vietnam and because of precautions necessitated by the COVID-19 pandemic in Indonesia, the pilot surveys were carried out using web-based forms. Web-based instruments may not be suitable for collecting data related to low-skilled occupations given the possibility that less-skilled workers have less access to digital technologies and low digital literacy.

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