I’m not so sure that’s true anymore. I don’t go looking at every single study but I usually see a mix of landline, cell/sms, and online samples
That is why I said most, not all.
About the Study
This Ipsos poll was conducted August 18-21, 2023 on behalf of Politico Magazine, using the probability based KnowledgePanel®. This poll is based on a representative sample of 1,032 U.S. residents, age 18 or older, including 272 Republican respondents, 321 Democratic respondents, and 319 independent respondents.
The study was conducted online in English. The data for the total sample were weighted to adjust for gender by age, race/ethnicity, education, Census region, metropolitan status, household income, and political party affiliation. The demographic benchmarks came from the 2022 March Supplement of the Current Population Survey (CPS). Party ID benchmarks are from recent ABC News/Washington Post telephone polls. The weighting categories were as follows:
Gender (Male, Female) by Age (18–29, 30–44, 45-59 and 60+) Race/Hispanic Ethnicity (White Non-Hispanic, Black Non-Hispanic, Other, Non-Hispanic, Hispanic, 2+ Races, Non-Hispanic) Education (Less than High School, High School, Some College, Bachelor or higher) Census Region (Northeast, Midwest, South, West) Metropolitan status (Metro, non-Metro) Household Income (Under $25,000, $25,000-$49,999, $50,000-$74,999, $75,000-$99,999, $100,000-$149,999, $150,000+) Party ID (Democrat, Republican, Independent, Something else)
The margin of sampling error is plus or minus 3.2 percentage points at the 95% confidence level, for results based on the entire sample of adults. The margin of error takes into account the design effect, which was 1.08 for all adults. The margin of sampling error is plus or minus 6.2 percentage points at the 95% confidence level, for results based on the sample of Republicans. The margin of error takes into account the design effect, which was 1.08 for Republicans. The margin of sampling error is plus or minus 5.8 percentage points at the 95% confidence level, for results based on the sample of Democrats. The margin of error takes into account the design effect, which was 1.11 for Democrats. The margin of sampling error is plus or minus 5.7 percentage points at the 95% confidence level, for results based on the sample of independents. The margin of error takes into account the design effect, which was 1.09 for independents. In our reporting of the findings, percentage points are rounded off to the nearest whole number. As a result, percentages in a given table column may total slightly higher or lower than 100%. In questions that permit multiple responses, columns may total substantially more than 100%, depending on the number of different responses offered by each respondent.