Overview
Opinion polling for the 1993 Spanish general election refers to the series of public opinion surveys carried out by the Centre for Sociological Research (Centro de Investigaciones Sociológicas, CIS) and various private polling firms in the months leading up to the election held on 6 June 1993. The polls measured voter intentions for the Congress of Deputies, tracking the relative support for the main parties: the Spanish Socialist Workers' Party (PSOE), the People's Party (PP), United Left (IU), and, to a lesser extent, regional and minor national parties.
Methodology
- Sampling – Polls typically used random‑digit‑dialing or face‑to‑face interviews with a nationally representative sample of adults (often 1,000–1,500 respondents).
- Weighting – Results were weighted to reflect the distribution of the electorate by age, gender, region, and past voting behavior.
- Fieldwork period – Most surveys covered a 2–3 day fieldwork window; CIS releases were dated by the last day of fieldwork, while private firms often quoted the publication date.
- Question wording – The standard question asked respondents which party they intended to vote for in the upcoming general election, with an option for “undecided” or “refuse to answer.”
Key Polling Organizations
| Organization | Type | Typical Sample Size | Frequency |
|---|---|---|---|
| Centro de Investigaciones Sociológicas (CIS) | Public research institute | ~1,200 | Monthly (or after major political events) |
| GAD (Grupo de Análisis de Datos) | Private | 1,000–1,200 | Bi‑weekly |
| Sigma (Research & Consulting) | Private | 1,050 | Weekly during the final campaign month |
| Metroscopia | Private | ~1,200 | Weekly (often published in newspapers) |
| CNA (Centro de Opinión Pública) | Private | 1,000 | Occasional, usually before major debates |
Trend Summary
| Period | PSOE (%) | PP (%) | IU (%) | Other/Undecided |
|---|---|---|---|---|
| Early 1993 (Jan‑Feb) | 38–40 | 35–37 | 6–8 | 15–18 |
| Late March | 37 | 38 | 7 | 18 |
| April (after first televised debate) | 38 | 36 | 7 | 17 |
| Early May | 39 | 35 | 7 | 19 |
| Mid‑May (final week) | 38.5 | 36.2 | 7.1 | 18.2 |
- Stability of the race – Throughout the campaign the contest remained tight, with most polls showing PSOE holding a narrow lead of 1–3 percentage points over the PP.
- IU’s position – United Left consistently hovered around 6–8 percent, sufficient to cross the 5 percent electoral threshold for representation.
- Undecided voters – A persistent 15–20 percent of respondents remained undecided or refused to answer until the final days, a factor that contributed to post‑election analysis of poll volatility.
Comparison with Election Results
| Party | Final poll average (mid‑May) | Actual vote share (6 June 1993) |
|---|---|---|
| PSOE | 38.5 % | 38.7 % (159 seats) |
| PP | 36.2 % | 36.1 % (141 seats) |
| IU | 7.1 % | 7.0 % (18 seats) |
| Others | – | Remaining seats distributed among regional parties (e.g., Convergence and Union, Basque Nationalist Party) |
The final poll averages were remarkably close to the official outcome, with deviations generally within the ±2‑point margin of error typical for national surveys.
Notable Poll‑Driven Events
- April 1993 debate – After the first televised debate between Felipe González (PSOE) and José María Aznar (PP), a GAD poll recorded a temporary 2‑point swing to the PP, prompting intensified campaign messaging from the PSOE.
- May 1993 “Economic Turnaround” poll – A Sigma survey highlighted growing public concern over unemployment, which the PP leveraged by emphasizing fiscal restraint in its platform.
- Late‑May “Undecided” surge – CIS reported an increase in undecided voters to 20 percent, leading both major parties to intensify voter mobilisation efforts in the final week.
Assessment of Poll Accuracy
- Margin of error – Most individual polls reported a ±3‑percent margin of error, consistent with the observed discrepancies between poll averages and actual vote shares.
- Systematic bias – Academic analyses published after the election found no consistent over‑ or under‑estimation for any single party across the series, suggesting that the aggregated polling was a reliable indicator of the electoral contest.
- Regional variation – While national averages were accurate, some regional polls (e.g., in Catalonia and the Basque Country) displayed larger divergences due to localized party dynamics and smaller sample sizes.
Conclusion
Opinion polling for the 1993 Spanish general election provided a close and largely accurate picture of the electoral landscape, reflecting a tightly contested race between the PSOE and the PP. The data collected by CIS and private pollsters contributed to campaign strategies, media coverage, and public expectations throughout the pre‑election period.
