lundi 18 août 2014

One month before, Scottish Independence & Quebec Sovereignty

Hi,

This is the last month before the referendum on Scottish independence, an appropriate moment to compare the current situation in Scotland and the situation that prevailed in 1995 in Quebec.

Scotland
First, let's examine the current situation in Scotland. With 49 polls published in 1995, one month to go, the likely situation right now is a gap of more than 10 points in favour of the No (12 points if we distribute the non-disclosers proportionally), as the following graphs show. Some have maintained that a rise in support for the Yes side have occurred last week. This is not obvious right now. As we can see, there is variation in the estimates published by the different pollsters. If we take that into account, we are still in a situation of no change in either direction. The impact of the debate held on August 5 may have been to reduce the proportion of non-disclosers (including mostly don't knows).

In evaluating the situation, we have to take into account the fact that half the polls, i.e.,  those conducted using opt-in panels by ICM, Survation and Panelbase, put support for the Yes side 4.5 points higher on average than the other polls (*see methodological notice at the end). If we look at all the elections where opt-in panels were compared to election results, we may conclude that these polls likely overestimate support for the Yes side. Let us now compare this situation with what happened in Quebec during a similar period to see if it can teach us something.



Quebec 1995
What was the situation in Quebec during about the same period? I kept all the polls -- including those conducted by academics, governmental agencies and political parties -- conducted between February 15, 1995 and Referendum Day, October 31th, 1995. I kept the results only when the question asked about vote for Sovereignty with an association with the rest of Canada. Before June 12 (first vertical line on the graph), when an agreement between Parti Québécois, Action Démocratique du Québec and Bloc Québécois -- called the 3-party agreement -- was signed, it was not clear what the question would be and whether a partnership with the rest of Canada would be part of it. Therefore, there are not many polls asking about this option before June 12. I have shown elsewhere that support differs according to the constitutional option -- independence, separation, sovereignty, sovereignty with partnership -- and that only the last option managed to reach majority support during some periods.

The first graph shows the change in support from February 15, 1995 to Referendum Day, including the non-disclosers. It shows that support for sovereignty with an association with the rest of Canada managed to get the support of a plurality of Quebeckers until two months before referendum Day. However, after the official launching of the campaign on September 7 (second vertical line on the graph), Support for the Yes side decreased to 40% and the proportion of non-disclosers increased until the last month. Then support for the Yes side went back up until referendum Day. The final two months are characterized by a roller-coaster type of movement and an increase in the proportion of non-disclosers (including don't knows).



The second graph shows the same information after proportional attribution of non-disclosers (**see methodological notice at the end).  Again, it shows a situation favorable to the Yes side, up until the launching of the campaign on September 7 and a roller-coaster ride afterwards.



Let's now focus on the last stretch. The third graph shows that, when the campaign was launched, the two sides were at par. Support for the Yes side went down during the first month so that one month before referendum Day, support for the Yes side was five to six points lower than support for the No. However, support for the Yes side went back up to finish 6 points higher than support for the No. However, as we can see, with proportional attribution of non-disclosers, support for the Yes was seriously overestimated. The referendum ended with 49.5% Yes and 50.5% No. With realistic (*) attribution of non-disclosers, the prediction of the results was almost perfect.



Conclusion - Scotland vs Quebec
There are a number of differences between the Quebec 1995 campaign and the Scottish 2014 campaign. For instance, the Quebec question pertained to sovereignty accompanied by an offer of  partnership to the rest of Canada and it was officially revealed less than two months before referendum Day. Independence per se (the Scottish option) never managed to get the support of a majority of Quebeckers in the polls.

In terms of poll results, the Quebec question managed to get the support of a short majority of Quebeckers during most of the period, which has not been the case in Scotland. When the Quebec Yes side increased its support during the last month in 1995, it was regaining support from people who had already been inclined to vote Yes at some point during the preceding months. Scotland's Yes side cannot rely on this possibility. It has to convince voters to change a position they held for months. Everything is still possible but, since no movement in support has occurred since March, the Scottish Yes side needs a very major event in order to gain the support of a majority of Scottish people. As the Quebec situation shows, it is possible to reverse the trend. In Quebec, a change in strategy -- i.e. the nomination of Lucien Bouchard as negociator in chief on October 7th -- seemed to have helped close the gap with the No side. However, Scotland's Yes side would probably need more than that. The current situation in Scotland resembles more to what happened in the first Quebec referendum in 1980 that ended with 59.6 for the No side than to what happened in the second referendum in 1995.

P.S. I will be away from August 24 to September 8. I will be back to monitor the last stretch.

* The other pollsters are TNS-BRMB (face-to-face), Ipsos-Mori (telephone) and YouGov (opt-in panel). These three pollsters had similar estimates since January. Note however that You Gov has just changed some features of its methodology (see here). It announced that it now includes respondents that are 16 and 17 year old (which means that they were not included in preceding polls!!) and that it modified its weighting scheme to take into account country of birth. YouGov states that its results for the last poll are not comparable with previous results and that the proportion of support for Yes Scotland is a bit higher with these new features.
** At that time, in Quebec, media and researchers alike tended to use a "realistic" attribution of non-disclosers that gave 75% of  them to the No side. This practice tended to put both sides almost equal and gave a very good prediction of the final result. Some Media published three figures, i.e., voting intention before attribution of non-disclosers, with proportional attribution and with "realistic" attribution.


lundi 11 août 2014

Polls on Scottish Independence: questions of methods



In this post, I first examine the current state of support for Scottish independence and second, I examine whether different methodological poll features are related to estimates, all else being equal.

The current state of support for Scottish independence

The following graphs show the change in support since January 2014. The first graph includes non-disclosers (don't knows & will not vote). Support seems rather stable since March 2014. The first graph shows a possible recent small increase in support for the No concurrent with a decrease in the proportion of non-disclosers. However, when non-disclosers are attributed proportionally to both sides (second graph), no such increase in  support for the No side is present. There is no significant relationship between the proportion of non-disclosers and support for each side (see below). Before attribution of non-disclosers, Yes is at 38% and No at 50%. After proportional attribution, the difference between the two sides is close to 15%, with the Yes slightly over 37% and the No at 52%.

Notice that in the following graphs, the time line is respected, which is not the case usually in the graphs presented on the different web sites and in the media.






Questions of methods

There was an interesting debate in Scotland on the weighting of opt-in web polls according to the recall of previous votes. In short, the question pertained to which election(s)  should be used for weighting. John Curtice's appraisal of the debate -- that took place between Survation and YouGov -- can be found here: Who is right? Survation or YouGov?  I quite share his appraisal that a)  the difference in estimates between YouGov and the three other pollsters using opt-in panels (ICM, Survation and Panelbase) cannot be due only to weighting and b) we do not have sufficient information to assess the cause(s) of this difference.

However, the interesting point here is that we have a systematic difference within the opt-in panel method. Therefore, we may think that there are specific features of opt-in panels (recruitment, selection, administration) that lend to different estimates. Usually, I check whether there is a difference between opt-in panels and other methods (I did find some in most elections held in Canada --see here and here). In the Scottish situation, I will also check whether there is a significant difference between YouGov, Ipsos-Mori (telephone) and TNS-Sofres (face-to-face) on one side and the opt-in panels carried by ICM, Survation and Panelbase on the other side.

I also address the question of whether the wording of the question makes a difference and whether the proportion of non-disclosers is related to support and to methods.



a) Administration mode

Controlling for time, opt-in web polls in general (including YouGov) estimate support for the Yes side, 3.1 points higher, on average, than the telephone and face-to-face polls. However, if we group YouGov with the telephone and face-to-face polls --which is justified by analysis of variance -- we conclude that the "other" opt-in web polls (Survation, ICM and Panelbase), estimate the proportion of Yes 4.6 points higher than the other polls.

In short, there is clearly a difference according to administration mode but YouGov's estimates are closer to the telephone and face-to-face polls' estimates than to the other opt-in panels.

b) Question wording

Question wording is related to mode of administration but it differs also between the different pollsters. I checked for two possibilities, i.e., whether the fact that Yes or No is specifically mentioned in the question makes a difference and whether the fact that the question asks how the respondent would vote now vs on September 18 makes a difference.

Mentioning specifically Yes or No does not make any difference, most probably because it is not relevant in Web Polls and because both Ipsos-Mori (telephone) and TNS-Sofres (face-to-face) mention Yes or No in their question.

The impact on the level of support of asking how the respondent would vote "now" vs "on September 18" varies depending on the variables that are present in the analyses. For now, I conclude that the difference noticed is more related each pollster's "cluster of methods" than to question wording itself.

c) Non disclosers

If there is one main difference between the pollsters, it is in the proportion of non-disclosers. All the firms differ significantly from each other in this regard. TNS-Sofres (face-to-face) has the highest proportion of non-disclosers -- an average of 28% -- while Ipsos-Mori (telephone) has the lowest -- 9.5%. One may ask whether TNS could reduce its very high proportion by improving its methods using for example, a secret ballot or a leaning question. The web polls  have proportions that are in between, from YouGov at 11.7% to ICM at 18.6%. Notice that, during the last month of the campaign in the Quebec 1995 referendum, the level of non-disclosers (telephone polls only) was around 13% on average and that the final turnout reached more than 95% (!).

It is also interesting to notice that:
  • There is no relationship between time and the proportion of non-disclosers. This proportion is solely related to the pollsters. It is a question of methods.
  • However, asking for voting intention "today" instead of "in September" is related to a decrease in the proportion of non-disclosers of more than 5 points. This is related to the different pollsters but is nonetheless very significant.

Conclusion

It is interesting to notice that the difference between opt-in web polls and other methods, and particularly between some web polls and other methods, is systematic and goes in the anticipated direction, i.e., a higher estimation of support for the Yes side. It should also be noticed that there is some research to be carried on why some web polls' estimates differ systematically from others.The other important point is the substantial difference in the proportion of non disclosers. This is clearly a question of methods since the proportion does not decrease with time. However, since it is not related to the proportion of support for each side, it has no clear impact on the estimate of support. Finally, as we get closer to the date of the referendum, the impact of asking voting intention for today vs for referendum day may fade out.

We are getting to the last month of the campaign. I will go on monitoring whether the impact of methods changes in the last stretch. However, in my next post, the focus will be on comparing Scotland with Quebec, and specifically with what happened during the last month (the official campaign) of the Quebec 1995 referendum.

jeudi 17 juillet 2014

Scottish Independence & the Young people

 Hi,

The question of young people's vote is interesting sociologically and politically. We expect young people to be more favorable to the Yes side in a referendum on independence because it proposes change. Young people may be more interested in change than in status quo. They may also be more easily convinced since they have not yet made up their mind definitely on many political issues. On the other hand, young people are accustomed to live in a globalized world. We may expect them not to be that interested in national States.

So what happens? I present first the situation in Scotland and then compare it with what happened and is now happening in Quebec regarding support for sovereignty among Young people.

Scotland

The following graph shows support for independence from January 2014 to the most recent polls among the whole population and among the 16 to 34 years old (purple line ). I computed a weighted average of the results by age group (age group by sex for Panelbase) presented by the different firms in order to arrive at a combined 16-34 age group*.

The graph shows that support for independence is very slightly higher among the 16-34 age group than among the general population. However, the difference is rather stable.



Quebec

The following graph shows the change in support for sovereignty for the three age groups between 1979, just before the first referendum in 1980, and 2014. The analysis is restricted to French-speaking Quebeckers -- usually defined as persons who speak mostly French at home -- since non-French speaking Quebeckers were generally opposed to sovereignty whatever their age.



The graph shows that before the first referendum in 1980, support for sovereignty among the 18-34 age group (47% of the population at that time) stand out compared to support among the two other age groups. It is at 63 percent compared to 36 percent for the 35-54 age group and 22 percent for the 55+ age group. The young people who were favorable to sovereignty in 1980 were still favorable in 1995 -- they constitute most of the 35-54 age group -- and they were joined by the new young people so that both the 18-34 and the 35-54 age groups were very favorable to sovereignty, at more than 63%, while support among the 55+ age group was at 40%.

This gave rise to the "dying federalist hypothesis" which stated that, as older people die, if  young people are still be more sovereigntist than older people and stay so as they grow older, sovereignty will eventually -- mathematically -- get the support of the majority of the population. This is not what happened. As we can see, after 2010, there is no more difference in support for sovereignty according to age which means that a) young people are not more sovereignist than the elder anymore and b) people do not necessarily stay sovereignist all their life. They may change their mind at some point.

In a presentation at IRPP in 2001, I also showed that only the less than 55 years old were influenced by the campaign in 1995. Support among those who were 55 years and older remained stable.

Another way to look at support for sovereignty according to age is illustrated by the following graph. The two upper lines -- blue for the 18-34, green for the 35-54 -- show that support for sovereignty increased among all French speakers after the 1995 referendum where the Yes side was defeated 50.5% to 49.5%. It started to decline around 2002, went up a bit around the Sponsorship scandal in 2004-2005, and finally went on declining. The point is that it declined more among the younger age groups than among the 55+ age group so that, in 2014, there is no difference left between the age groups.


Conclusion

The situation in Scotland seems closer to the actual situation in Quebec than to the situation that prevailed in Quebec on the eve of the two referendums. Support for independence does not differ much between age groups and it changes similarly among the young people than among the general population. The hypothesis that young people do not differ much from older people in their political positions is the most plausible for now. 


* Methodological note: Sample sizes of smaller age groups -- 16-24, 25-34 -- were way too small to use the results with some confidence. These results vary enormously from one poll to the next and from one age group to the next. In addition, there were some differences in the age groups used by the different firms. I computed a weighted average of the support of the 16-24 and 25-34 age groups. For YouGov -- who uses a 25-39 age group -- I considered it to be an estimate of the support among the 25-34 age group and I applied the same weights as for the other firms. For Panelbase, who presents results for males 16-34 and females 16-34, I used a weight according to sex.

mercredi 9 juillet 2014

Scottish Independence, Quebec Sovereignty, similar or not?

Hi,

First, my apologies to French-Speaking followers since I am going to write my messages on the Scottish referendum solely in English. And apologies to English speakers too: My English writing is not perfect.

The referendum campaign for Scottish independence is under way. It is the first time where it is possible to compare a political campaign with the referendum campaign pertaining to Quebec sovereignty in 1995. The Quebec referendum was held on October 31th 1995 and ended with a very close result, i.e. 50.5% No and 49.5% Yes. The turnout was around 95%. In both situations, the movement for Independence is taking place in a developed country that is part of the Commonwealth.

For this first post, I will compare the Scottish polls with the Quebec polls during similar periods and I will address the question of attribution of preferences to non disclosers, i.e. respondents who do not reveal a preference or state that they will not vote. In following posts, I will address the question of whether there are differences between polls' estimates according to the methodology used --  mode of administration, question wording, etc. -- and I will deal with the question of whether young people's preferences differ from older people's.

What is the state of public opinion? 

a) Including non disclosers


The following graph shows the evolution of support for Scottish Independence. The non-disclosers -- all those who say they don't know how they will vote or state that they and will not vote -- are  included in the graph.


It shows that although there was a possible increase in support for Independence from January to March, support seems to be going back to what it was at the beginning of the year. In addition, we see that there is much variation between the estimates from the different pollsters. The proportion of Yes is at about 35% but it varies between less than 30% and close to 43%. The proportion of No is close to 50% on average but the range of estimates is also large, i.e. 10 points. Finally, the proportion of non disclosers stays between 10% and 20% except for some specific polls where it reaches 30% or more. Those polls were generally conducted face-to-face.

If we look at a similar period in Quebec, i.e. January to June 1995 -- the referendum was to be held on October 30th -- we get a quite different portrait. Notice that since the question wording had not been decided yet at that time in Quebec, pollsters used different wordings and tested support for different options and according to different wordings. In order to have enough data as well as a relatively homogenous information, I kept the estimates for all the questions pertaining to a vote for either sovereignty per se or sovereignty with an association with the rest of Canada. Here is the portrait:



In the Quebec situation, we notice first that the Yes and No sides was closer than it is in Scotland and second, that the proportion of non-disclosers decreased in the last weeks before summer with a concurrent increase in both Yes and No support.

b) A few words about the non-disclosers

Is there a relationship between the proportion of non-disclosers in the polls and the distribution of Yes and No. The clear answer to that is that for these periods, there is absolutely no significant  relationship between the proportion of non-disclosers and the distribution of support for Yes and No in Scotland as well as in Quebec. In Quebec however,  following suggestions from researchers -- Maurice Pinard, Pierre Drouilly -- based on empirical findings, there has been a tendency to attribute more non-disclosers to the No side -- between 67% and 75% -- than to the Yes side. The rational for this practice was that the socio-demographic profile of the non-disclosers is more similar to the profile of No voters -- more likely to be older, for example -- than of Yes voters. This practice allowed for a very good estimate of the referendum results in 1995. Without it, the predictions would not have been accurate.

Should Scottish pollsters proceed to a non proportional attribution of non-disclosers? This question should be examined. In any case, it is highly possible that the No side is underestimated since when polls are not accurate, it is usually the status quo side, the more conservative side of the electorate, that is underestimated.

c) Excluding non-disclosers, with proportional attribution

If we exclude the non-disclosers, we have to decide how to attribute them between Yes and No. The common use is to do it proportionally. The hypothesis here is that the preferences of those who do not reveal a preference are similar to to the preferences of those who do reveal them. Notice however that this means that when the proportion of No is close to 60%, proportional attribution gives to the No side a proportion that is close to the non proportional distribution that was used in Quebec. In short, non proportional attribution has a more substantial effect when the distribution of Yes/No is close to 50%.

Here is the portrait of the evolution of support for Independence in Scotland with proportional attribution of non-disclosers:



 It shows the No  side between 55% and 60% with the difference between Yes and No being close to 15%, and no overlap of Yes and No, whatever the poll.

Now, let's see what was the situation in Quebec at about the same period with a similar proportional attribution of non disclosers.  The graph shows that at most, there was a 10 point gap between Yes and No around the middle of March. By May, the gap had closed and, by the end of June, the difference between Yes and No was 5 to 6 points .


Conclusion:

In Quebec as in Scotland, the campaign started with a deficit for the Yes side. However, the deficit was clearly less substantial in Quebec than it is right now in Scotland. Campaign dynamics vary within and between countries. It will be interesting to follow the Scottish situation and examine the methodological questions that it will raise. Will opt-in panels -- more than two-thirds of the polls -- overestimate the Yes side? Will polls in general be accurate using a proportional attribution of non disclosers? How will young people vote? Will they be much more favorable to Independence like in 1995 in Quebec or will they have similar preferences as the other age groups, like the current situation in Quebec?


P.S. Methodological information for specialists: The lines -- the likely evolution -- are estimated  using weighted local regression (loess) with Epanechnikov estimation using 65% of the points for adjustment. In various trial and error with different "smoothers", it appeared the best ans most flexible compromise and it gave very good results in the last Quebec election in 2014.



vendredi 13 juin 2014

Post-Mortem Ontario: Who's right?

Hi,

How did the pollsters fare in this election? There are a number of different ways to look at the situation. The first is to see whether the prediction that I made using all the polls' estimates was accurate.  Here is the graph with the election results:




 It is clear from this graph that the Liberals were globally well predicted by the polls but that, contrary to usual, the PC was overestimated and the NDP underestimated. This a rather rare situation. In the last federal election of 2011, the polls had underestimated the PC by more than 4 points in Ontario.

Who's right? 

There is a debate around methods and pollsters. Who fared better? There are known ways to deal with this. One is to calculate the difference between the results and the estimates from the polls. The relative error (results minus estimates) tells us whether a party tended to be over or underestimated by the polls. A positive result means that the party was underestimated by the polls. The absolute error infoorms on the level of the difference between the results and the estimates. The total absolute error gives the synthetic information on the global level of error. It is computed as the sum of the absolute error for the three main parties. I present the results grouped by method (IVR vs Web) for the polls conducted from June 5 in the table at the end of the message.

What the table and my analyses show is:
  • IVR polls got the Liberals right (mean error of -0.34) but they overestimated the PC by 3.6 points and underestimated the NDP by 5.1 points on average.
  • Web polls underestimated the Liberal party by 3.7 points on average and overestimated both the PC (2 points) and the NDP (2.3 points).
  • The difference between the estimates of IVR polls and Web polls is significant for the Liberals and the NDP. We are still in a situation where Web polls tend to overestimate the NDP.
  • As for the absolute difference, it is rather large -- between 2 and 5 points on average. There is no significant difference between the IVR and the WEB polls.
  • If we look at the total absolute error, it is 10.8 points on average for the IVR polls and 9.6 for the WEB polls. Again, there is no significant difference between these two averages.
A total absolute error of 10.8 is rather high. It is however lower than what has been seen in BC2013 and Alberta 2012.

In conclusion,

The surprise with this election is the global underestimation of the NDP and the overestimation of the PC. I do not see how to explain this. The only expected bias, i.e. an overestimation of the NDP vote and an underestimation of the PC vote by the WEB surveys indeed happened. The huge underestimation for the NDP vote by the IVR polls will have to be analyzed by the pollsters. In addition, the "likely voter models" did not seem to perform adequately. It is good that pollsters who used these models indeed published also their figures for eligible voters. Analyst and voters could see that polls allowed for different estimates according to different hypotheses about who is participating in the election. However, the likely voter models do not seem to be "the solution" to bias in polls' estimates. Pollsters who use IVR should perhaps think about introducing cell phone numbers in their samples and see whether it improves their estimates.

The final point to notice -- it has been noticed by many analysts -- is the substantial variation between estimates. This means that the methods right now are not at the level of reliability that we would like to see them.



Error of the polls - 2014 Ontario Election

Method Pollster mid-date of field period error LIB error PC error NPD Abs. error LIB Abs. error PC Abs. error NDP Total absolute error
IVR Forum 06-JUN-2014 -0.3 -5.8 6.7 0.3 5.8 6.7 12.8
  Ekos 07-JUN-2014 2.8 -4.7 6.1 2.8 4.7 6.1 13.6
  Forum 10-JUN-2014 -3.3 -3.8 4.7 3.3 3.8 4.7 11.8
  Ekos 11-JUN-2014 1.4 -0.1 4.5 1.4 0.1 4.5 6.0
  Forum 11-JUN-2014 -2.3 -3.8 3.7 2.3 3.8 3.7 9.8
                   

Mean   -0.34 -3.64 5.14 2.02 3.64 5.14 10.80

Median   -0.30 -3.80 4.70 2.30 3.80 4.70 11.80

Std. error of mean   1.13 0.96 0.55 0.53 0.96 0.55 1.36
                   
WEB Ipsos 05-JUN-2014 3.7 -3.8 -2.3 3.7 3.8 2.3 9.8
  Abacus 06-JUN-2014 4.7 0.2 -4.3 4.7 0.2 4.3 9.2
  Angus Reid 09-JUN-2014 2.7 -0.8 -2.3 2.7 0.8 2.3 5.8
  Ipsos 09-JUN-2014 5.7 0.2 -6.3 5.7 0.2 6.3 12.2
  Leger 09-JUN-2014 1.7 -5.8 3.7 1.7 5.8 3.7 11.2
                   

Mean   3.70 -2.00 -2.30 3.70 2.16 3.78 9.64

Median   3.70 -0.80 -2.30 3.70 0.80 3.70 9.80

Std. error of mean   0.71 1.20 1.67 0.71 1.13 0.74 1.09
                   
Total                  

Mean   1.68 -2.82 1.42 2.86 2.9 4.46 10.22

Median   2.20 -3.80 3.70 2.75 3.80 4.40 10.50
  Std. error of mean   0.92 0.77 1.49 0.50 0.74 0.49 0.84


mercredi 11 juin 2014

Pendant ce temps, en Ontario

Bonjour,

Je ai suivi les sondages en Ontario entre autres pour voir si la même méthode que j'ai utilisée pour l'élection québécoise de 2014 pouvait donner de bons résultats. De plus, comme j'ai analysé les sondages de la campagne de l'Alberta en 2012 et celle de la Colombie Britannique en 2013, je me suis intéressée à la comparaison entre les campagnes.

Mes remerciements à Bryan Breguet (Too close to call) qui m'a fourni les informations qu'il avait récoltées et avec qui j'ai pu échanger pendant la campagne.

Voici ce que donne l'évolution des intentions de vote:



Les derniers sondages tendent à montrer une remontée du parti Libéral qui le situerait aux alentours de 37,5% des voix alors que le PC serait plutôt à 34% environ. La tendance serait également à une baisse des intentions de vote pour le NPD qui se situerait à un peu plus de 20%. Toutefois, ces évolutions ne sont pas significatives. En clair, les trois lignes pourraient être simplement des lignes droites et il  ne reste plus de temps pour voir la suite. Ce sera donc l'élection qui dira si la tendance est réelle.

Quelle fiabilité accorder à ces résultats? On a en mémoire les "catastrophes" de l'Alberta en 2012 et de la Colombie-Britannique en 2013 de même que la sous-estimation du PLQ au Québec en 2012. Ces élections ont en commun de s'être déroulées dans des circonstances où il y avait un parti qui était au pouvoir depuis longtemps, une certaine insatisfaction par rapport à ce parti et une volonté de changement. Par contre, l'alternative au parti au pouvoir était loin de faire l'unanimité. Il me semble que la situation est similaire en Ontario et les conséquences peuvent également être similaires, soit que le parti au pouvoir fait finalement mieux que prévu.

Du côté des sondages, mes analyses montrent qu'en Ontario, tout comme pour l'élection de Colombie Britannique en 2013, les sondages Web surestiment le NPD au détriment du parti Libéral si on les comparent aux sondages fait par téléphone. De plus, lorsque les sondages se trompent, ils le font à peu près toujours dans la même direction: ils sousestiment le parti le plus à droite, ici le PC, et surestiment le parti le plus à gauche, soit le NPD. Enfin, les partis qui n'ont pas de chances de prendre le pouvoir, dans ce cas-ci le NPD et les Verts, sont généralement surestimés. Ceci semble dû en partie au fait que les électeurs de ces partis sont moins enclins à aller voter.

En conclusion, si les sondages se trompent, le NPD est le plus susceptible d'être surestimé et le PC, le plus susceptible d'être sousestimé. Les Libéraux pourraient également être un peu sousestimés. Je n'ai malheureusement pas pour l'Ontario un historique de la performance des sondages qui me permettrait de corriger les estimations en conséquence.

Au plaisir

mardi 3 juin 2014

Générations, souveraineté, Parti Québécois,

Bonjour,

Dans La Presse aujourd'hui, un article de Katia Gagnon  Souveraineté du Québec: le projet de deux générations basé entre autres sur une analyse que j'ai faite de 125 sondages réalisés par CROP depuis 1976, disponibles entre autres sur CORA (Archives canadiennes des sondages d'opinion publique).

Comme tous les graphiques ne sont pas disponibles dans La Presse "ordinaire" ou sur Cyberpresse, je les mets à la suite.

Pourquoi dire qu'il s'agit du projet de deux générations? Parce que, en 1980, seuls les moins de 35 ans sont plus souverainistes que les autres groupes d'âge. En 1995, malgré que le Parti Québécois avait "abandonné" la souveraineté au profit du beau risque et de l'affirmation nationale pendant quelques années avant le retour de Jacques Parizeau, deux groupes d'âge deviennent "porteurs" de la souveraineté. D'une part, les moins de 35 ans de 1980 -- devenus les 35-54 ans -- qui sont demeurés souverainistes dans une large proportion ou qui le sont redevenus à la faveur de la campagne référendaire. D'autre part, les nouveaux jeunes, les moins de 35 ans de 1995, qui eux aussi sont convaincus par la campagne de 1995. Il s'agit donc de deux générations, ceux qui sont nés entre 1945 et 1962 -- les baby-boomers -- et ceux qui sont nés entre 1962 et 1977. On peut voir les graphiques sur l'appui à la souveraineté selon l'âge plus précisément entre 1995 et 2000 ici.

Les graphiques montrent que les générations suivantes n'ont pas pris le bateau. Est-ce qu'elles auraient pu le prendre à la faveur d'une campagne référendaire? Il s'agit d'une question hypothétique et deux hypothèses peuvent être posées. Certains postulent que "les jeunes d'aujourd'hui sont rendus ailleurs" et donc que, quels que soient les arguments amenés lors d'une campagne référendaire, ils ne seront pas convaincus. D'autres postulent que les jeunes sont plus "mobiles" politiquement et peuvent être convaincus à la faveur d'une campagne référendaire. C'est ce qui s'est passé pendant la campagne de 1995 au Québec. Je tenterai de tester ces hypothèses dans le cadre du référendum sur l'indépendance de l'Écosse.

Évolution de l'appui à la souveraineté 1977-2014:


Évolution de l'appui à la souveraineté 1996-2014 (Zoom du graphique précédent).

Évolution de l'appui à l'intention de vote pour le Parti Québécois 1977-2014:


Évolution de l'appui à l'intention de vote pour le Parti Québécois 1996-2014 (Zoom du graphique précédent: