Misleading abortion poll results

David Farrar has posted  Poll on abortion which repeats some what I thought were misleading poll results, unless you look carefully.

Curia did polling in January for ALRANZ to ascertain views of New Zealanders on whether abortion should be legal in different circumstances.  I thought the results were very interesting with the net level of support (those saying legal less those saying illegal) for each situation being:

  • Pregnant woman likely to die +72%
  • Foetus has no chance of survival +70%
  • Pregnant woman likely to be permanently harmed +70%
  • Pregnancy is a result of rape +65%
  • Pregnancy is a result of birth control failure +31%
  • Pregnant mother can’t afford to have another child +27%
  • Pregnant woman doesn’t want to be a mother +22%

Note that those percentages are “the net level of support (those saying legal less those saying illegal)”, not the actual percentages of responses.

This repeats how the results are displayed on the Abortion Rights Aotearoa in 2017 National Abortion Poll Results. If you click through to the Full Poll Results and Data  you get a different set of numbers:

The level of support for abortion being legal in each situation is:
1. Pregnant woman likely to die 77%
2. Foetus has no chance of survival 76%
3. Pregnant woman likely to be permanently harmed 76%
4. Pregnancy is a result of rape 73%
5. Pregnancy is a result of birth control failure 55%
6. Pregnant mother can’t afford to have another child 54%
7. Pregnant woman doesn’t want to be a mother 51%

The level of support for abortion being illegal in each situation is:
1. Pregnant woman likely to die 5%
2. Foetus has no chance of survival 6%
3. Pregnant woman likely to be permanently harmed 6%
4. Pregnancy is a result of rape 8%
5. Pregnancy is a result of birth control failure 24%
6. Pregnant mother can’t afford to have another child 27%
7. Pregnant woman doesn’t want to be a mother 29%

They follow that with the net results as posted in their Executive Summary and on Kiwiblog, but I think that is not how most people expect to see results and in fact I think appears to understate support for abortion rights.

This seems odd given that the poll was commissioned and published by Abortion Law Reform Association of New Zealand.

They have a table that gives better clarity.

AbortionPollJan2017

Poll details:

CLIENT: Abortion Law Reform Association of New Zealand
POLL DATES: Sun 22 to Mon 30 January 2017. The median response was
collected on Thu 26 January 2017.
TARGET POPULATION: Eligible New Zealand voters.
SAMPLE POPULATION: Eligible New Zealand voters who are contactable on a landline.
SAMPLE SIZE: 1,000 respondents agreed to participate.
SAMPLE SELECTION: A random selection of 15,000 nationwide phone numbers.
WEIGHTING: The results are weighted to reflect the overall voting adult
population in terms of gender, age, and area.
SAMPLE ERROR: Based on this sample of 1,000 respondents, the maximum
sampling error (for a result of 50%) is +/- 3.1%, at the 95% confidence level.