Dyadic Representation in a Westminster System

• DOI: http://doi.org/10.1111/lsq.12148
• Author: Benjamin E. Lauderdale,Chris Hanretty,Nick Vivyan
• Date: 01 May 2017
• Published date: 01 May 2017

CHRIS HANRETTY

University of East Anglia

BENJAMIN E. LAUDERDALE

London School of Economics and Political Science

NICK VIVYAN

Durham University

Dyadic Representation in a

Westminster System

Is policy representation in contemporary Westminster systems solely a function

of programmatic national parties, or does the election of legislators via single-member

districts result in MPs whose policy positions are individually responsive to public opin-

ion in their constituencies? We generate new measures of constituency opinion in

Britain and show that, in three different policy domains and controlling for MP party,

the observed legislative behavior of MPs is indeed responsive to constituency opinion.

The level of responsiveness is moderate, but our results do suggest a constituency-MP

policy bond that operates in addition to the well-known bond between voters and

parties.

Introduction

For countries that elect their legislators using single-member dis-

tricts (SMDs), one fundamental form of substantive representation

(Pitkin 1967, 222–24) is the degree to which the policy positions of legis-

lators ref‌lect the policy preferences of their constituents—a form of

representation that has become known as dyadic representation

(Weissberg 1978, 536). To the extent that SMD elections are contested

by “responsible” (Katz and Wildenmann 1987, 7)—i.e, cohesive and

programmatic—national parties, some degree of dyadic representation is

guaranteed: If each constituency chooses between candidates based on

their party’s programme, and each legislator faithfully supports their

party’s programme, this by itself will lead to an association between con-

stituency opinion and legislator policy position (Ansolabehere, Snyder

and Stewart 2001; Miller and Stokes 1963). But does the electoral link-

age between individual legislators and their constituents created by

LEGISLATIVE STUDIES QUARTERLY, 42, 2, May 2017 235

DOI: 10.1111/lsq.12148

V

C2016 The Authors Legislative Studies Quarterly published by Wiley

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This is an open access article under the terms of the Creative Commons

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medium, provided the original work is properly cited.

SMDs also result in within-party policy responsiveness, whereby the

policy positions of individual legislators within the same party co-vary

with opinion in their particular constituencies?

1

In the United States, where the vast majority of research on dyadic

representation has been conducted, the answer appears to be a qualif‌ied yes

(Ansolabehere, Snyder and Stewart 2001; Clinton 2006, 401; Kastellec,

Lax and Phillips 2010; Krimmel, Lax and Phillips 2016). Yet outside

of the United States research on dyadic representation is much less

developed (Powell 2004, 283–84). Indeed, with some rare exceptions

(Converse and Pierce, 1986), scholars have yet to empirically demon-

strate the existence of dyadic representation in many countries that

have SMD electoral systems, much less establish whether any dyadic

representation that does emerge is entirely due to responsible national

parties or at least in part due to within-party policy responsiveness.

This is unfortunate because the United States i s somewhat unusual

among SMD systems, with its relatively weak party cohesion and more

individualistic electoral competition (Bawn and Thies 2003; Carey and

Shugart 1995; Dalton, Farrell and McAllister 2011), making it an envi-

ronment particularly conducive to within-party policy responsi veness.

Westminster systems appear to present a far more challenging

environment for within-party policy responsiveness, characterized as

they are by parliamentary government with strong executive agenda-

setting powers, resulting in highly disciplined parties that compete

electorally on national policy platforms (Bawn and Thies 2003; Cox

1987). Focusing on the United Kingdom as a case study, this article asks

whether party dominance completely precludes within-party policy

responsiveness in a Westminster system, or whether, even accounting

for party, there remains some association between the policy positions

of individual Members of Parliament and policy opinion in the

constituencies they represent.

While we are not be able to establish a causal mechanism here,

even establishing the descriptive fact that such an association exists

speaks to important normative and practical debates about the merits of

Westminster systems. This is because the “strong voter-member link-

ages” purportedly fostered by SMDs in Westminster systems are

commonly highlighted by opponents of electoral reform as one of the

main reasons why the well-acknowledged costs of SMD elections—

chief‌ly, high levels of disproportionality (Carey and Hix 2011)—are

worth bearing (Norris 2001, 877).

2

Studies have documented evidence

that such voter-member linkages are manifest with respect to MPs’ non-

policy, constituency service-type behaviors (Cain, Ferejohn and Fiorina

1987; Norton and Wood 1993; Rush 2001; Searing 1994) and with

236 Chris Hanretty, Benjamin E. Lauderdale, and Nick Vivyan

respect to the policy issues that MPs choose to attend to (Blidook and

Kerby 2011; Soroka, Penner, and Blidook, 2009). However, research on

voter-member linkages with respect to policy positions has to date been

impeded by a lack of the required empirical measures.

Establishing the existence of within-party policy responsiveness

would also point toward a previously underappreciated channel for poli-

cy representation in Westminster systems. Kam et al. (2010) have

provided evidence that the policy positions of backbench MPs in the

Commons signif‌icantly constrain party leaders, the actors assumed to

dominate the policymaking process in Westminster systems. They spec-

ulate (301) that this inf‌luence of rank-and-f‌ile MPs could mean that

nonmarginal constituencies have more inf‌luence in the policymaking

process than previously thought (Kam et al. 2010, 201). Of course, this

only holds if it can be shown that, within a party, MPs’ policy positions

ref‌lect those of their constituents.

There are two main reasons why it has previously been so diff‌icult

to directly test for within-party policy responsiveness. First, it is expen-

sive to obtain accurate estimates of constituency policy opinion through

mass surveys. Although the per-respondent cost of opinion surveys has

decreased over time, sampling even a small number of respondents in

each of the 632 constituencies in mainland Britain quickly yields total

sample sizes in the hundreds of thousands. Second, it is diff‌icult to mea-

sure individual legislators’ policy positions. The British Representation

Study (e.g., Norris and Lovenduski 1992, 1997, 2001) has surveyed pro-

spective parliamentary candidates at many recent general elections and

asked them to indicate their position on different policy dimensions;

however, these measures suffer from low response rates (Kam et al.

2010) and cannot be linked to particular constituencies because they are

always collected on the condition that “individual replies will be treated

in the strictest conf‌idence” (Kam et al. 2010, xx). Strong party discipline

also means that differences of opinion between members of the same

party are often reconciled privately (Cowley 2002, 183; Norton 1999),

or, if they are made visible in legislative votes, are only done so in ways

incompatible with the models of sincere voting upon which many scal-

ing techniques rely (Spirling and McLean 2007).

In this article, we capitalize on recent methodological advances to

overcome these two diff‌iculties. We use methods of small-area estima-

tion to generate estimates of constituency opinion both on a general left-

right economic scale and on specif‌ic issues (same-sex marriage and the

European Union). We then show how variation in constituency opinion

is associated with within-party variation in MP positions as revealed by

scaled Early Day Motion signatures (“unobtrusive measures” of

237Dyadic Representation in a Westminster System