Abstract
While the role of legislators in parliamentary systems may sometimes seem to involve little more than to support the government of the day, legislators in many parliaments regularly take advantage of their, often limited, opportunities to introduce members’ bills and parliamentary motions. The success of these efforts is typically limited, which raises the question of why legislators bother. We argue that the legislators’ behavior is in part driven by the incentives their parties present them with. Government and opposition MPs behave in a different manner because government and opposition parties value legislative activity and types of legislative activity differently. Government MPs are expected to stay out of the way of the government’s agenda or focus their attention on less salient issues. In contrast, opposition MPs are expected to do the opposite and to present their parties as viable government alternatives. Examining members’ bills and parliamentary motions in Iceland over a thirty-year period, we observe patterns consistent with the importance of parties in shaping legislative behavior, while also finding some evidence of MPs’ career concerns affecting their behavior.
While most legislatures afford individual legislators the opportunity to introduce legislative proposals, the work of the legislatures tends to be structured by political parties—even where constitutions do not ascribe an important role to parties. There are, naturally, differences across legislatures, and there is, in particular, an important difference between presidential and parliamentary legislatures. The dependence of the executive on the legislature’s confidence in parliamentary systems has important implications, as the failure to pass government legislation can be construed as a loss of confidence. While this gives the appearance that the legislature holds the reins, it is really the opposite. The risk of unseating the government results in greater demands for party discipline, which government parties enforce, for example, using their control of access to positions in the cabinet and legislature (Kam, 2009).
Accordingly, in most parliamentary systems, most legislation is introduced by the government. While legislators propose legislation, it tends to be far less likely to be adopted. Brunner (2013), examining 14 countries, finds that passage rates for members’ bills are typically less than 10%. In, for example, Italy and Portugal, the rates are significantly higher at 17.4% and 33.5%, but these outliers may be explained by the inclusion of Senate bills in Italy and a high cosponsorship requirement in Portugal. 1 Despite this, legislators do not appear to be deterred by the slim chances of adoption. Members’ bills often outnumber government bills in countries that place few restrictions on the right to propose legislation. This raises the question of what motivates legislators to introduce members’ bills?
Why do MPs introduce legislative proposals?
The lack of attention members’ bills have attracted is perhaps a testament to how rarely they are successfully adopted into law. In terms of cross-national research, two chapters in Döring’s (1995) discuss members’ bills and their success rates (Andeweg and Nijzink, 1995; Mattson, 1995). In the thirty years since, only Brunner (2013), building on Ismayr (2008) appears to report cross-national information. The literature at the country-level is not much more substantial. Even in the countries that have received the most attention, the UK and Canada, the literature is hardly extensive. 2 Studies have sought to exploit the random selection of members’ bills in Canada, New Zealand, the UK, and Wales to examine the electoral consequences of introducing members’ bills (Bowler, 2010; Loewen et al., 2014; Williams, 2018; Williams and Indridason, 2018). Däubler et al. (2016) similarly find that introducing legislation increases the personal vote of Belgian MPs in the context of flexible-list system.
The underlying assumption in this literature is that legislators’ motive for offering private members’ bills and parliamentary motions is that it improves their electoral prospects. Solvak and Pajala (2016) take a more direct approach to examine whether the personal vote matters, and ask whether the incentives generated by electoral systems translate into MPs offering more members’ bills. Kellermann (2013) and Fleming (2022) find that MPs in more competitive districts are more likely to offer, respectively, early day motions and private members’ bills in the UK. On the whole, however, there is not much evidence that suggests that legislators only propose private members’ bills in electoral systems that reward personal vote-seeking.
Brunner (2013) offers perhaps the most comprehensive exploration of the motives behind the introduction of members’ bills. Examining data on bill initiation in Belgium, France, Germany, and the UK, he finds that members’ bills are used to signal MPs’, or their party’s, policy positions to voters and that legislators do so strategically, that is, they are more likely to offer private members’ bills on issues where their position is central (and, thus, more likely to be popular). Legislators are also found to respond to public opinion by being more likely to propose private members’ bills on issues where the public is engaged. Legislators may also use private members’ bills to highlight how they differ on policy from their party when they perceive that doing so will be electorally beneficial.
Theory
Parties in parliamentary systems often wield great influence over the careers of their MPs, which can include ballot access and positions, as well as access to offices within the party and in the legislature. In such circumstances, MPs will want to signal competence, loyalty, and effort in the hope of securing access. If MPs have an incentive to tailor their legislative behavior to their party, then their behavior should vary, for example, depending on whether their party is in government or the opposition. 3 Party leaders’ expectations about MPs’ legislative activity depend on whether they are in government or not. For a government party, a “good” MP votes with the party and does not get in the way of the government’s agenda otherwise—government MPs should not waste precious time in the legislature by introducing legislation or motions. Opposition parties are unlikely to impose similar constraints on their MPs. The opposition, in general, has limited means to influence legislation, and to some extent, its ability to influence comes from disrupting the government’s agenda. Thus, opposition parties have much less to gain from restraining their MPs, and may even welcome their proposals.
Government MPs introduce fewer private member proposals than opposition MPs.
We do not expect MPs’ incentives to offer bills and motions to differ much—both can serve to signal what the MP stands for. Formally, members’ bills are concrete proposals for a change, while parliamentary motions are expressions of the preferences of the parliament—often in the form of directions to the government to address a particular policy problem. In general, we do not know much about the role of parliamentary motions, but the choice between offering a bill or a motion may depend on factors such as the complexity of the issue and the potential for reaching an agreement. 4 In terms of affecting the incentives of MPs to offer proposals, we expect that government MPs shy away from bills in favor of motions as motions may be perceived to interfere less with the government’s agenda. For the same reason, opposition MPs may prefer bills.
Relative to opposition MPs, government MPs will show a preference for parliamentary motions over bills.
While MPs may depend on their parties in important ways to secure re-election, re-election may sometimes also depend on factors that are more directly under the MPs’ control and re-election concerns are likely to be among the motives influencing legislative behavior. Introducing legislation and motions may help the electoral prospects of MPs in different ways. Most directly, they may signal to voters that the MP seeks to advance the interests of their constituents. These incentives should be most relevant when the MPs’ electoral fortunes are directly influenced by their personal vote (Carey and Shugart, 1995). Similarly, MPs elected in primaries should be better attuned to their constituents than colleagues whose seats are allocated by the party leadership (Rahat and Hazan, 2001; Tuttnauer and Rahat, 2025). Thus, we expect MPs who earned their seat through primaries to be more sensitive to constituency concerns. Similarly, we expect MPs who were the last ones to be elected off their party’s list to be motivated to propose bills and motions out of concern for their electoral security.
MPs under electoral pressure are more active in offering private member proposals.
While MPs who rely more on the personal vote should have a greater incentive to propose legislation to signal effort or policy positions to their constituents, that incentive is likely tempered for government MPs. Even when government MPs do not depend on the party for favorable positions on the party list, the party controls access to various legislative and executive positions that they can use to rein in their MPs (Kam, 2009). While opposition parties, by virtue of their position, have less opportunity to punish their members, the threat of being barred from access to those positions in the future can be used to maintain discipline. However, opposition parties have little incentive to ask their members not to propose legislation or motions. Thus, while the personal vote is expected to make all MPs more likely to propose legislation and motions, the effect should be more pronounced among opposition MPs.
The effect of primary participation and occupying a marginal seat on proposal activity is greater for opposition MPs than for government MPs.
The MPs’ ideological preferences may also influence their propensity to propose legislation and motions. One might expect MPs at odds with their party, for example, on issues beneficial to their constituencies that do not align with their party’s platform, to be more likely to offer proposals. That is, MPs may want to signal their policy positions to their constituents. If that is the case, MPs whose policy preferences are less aligned with their party may be more likely to offer proposals. This incentive is likely to be stronger for MPs whose re-election prospects depend on their personal vote, but weaker for government MPs.
MPs whose ideal points are further from the party median introduce more proposals.
Our emphasis on the importance of parties in shaping the incentives facing MPs suggests a different set of expectations. Government MPs should generally be less likely to offer proposals, but those that do are more likely to be those whose preferences align with the party, that is, only proposals that are seen to complement the party’s agenda will be seen in a favorable light. In contrast, opposition MPs, by virtue of being unlikely to interfere with the advancement of their party’s agenda, will face fewer such constraints. Thus, ideological distance from the party median should have a greater impact for opposition MPs than government MPs.
MPs may also simply be motivated by a desire to influence policy. This may be especially relevant on issues that may attract support from across parties. The urban-rural cleavage has some importance in Icelandic politics and promoting issues beneficial to rural constituencies may be important to rural MPs (and even their parties). Thus, we expect rural MPs to offer more proposals.
MPs from rural constituencies propose more bills and motions.
Members’ proposals are, however, unlikely to pass, but MPs may have the more modest aim of attracting attention and forcing an issue onto the political agenda. To do so, it is important to demonstrate support for the proposal, whether in terms of the number of MPs supporting it or the number of votes in its favor if it makes it that far. The first step in demonstrating support for a proposal is likely to involve the MP’s co-partisans—if an MP is unable to win co-partisans over, the proposal’s prospects are going to be dim. Thus, if policy-concerns motivate legislators, MPs who are most closely aligned with the party should be more likely to introduce proposals—either because the substance of their proposals is more likely to reflect the party’s agenda or simply by virtue of the MP being perceived as being a representative member of the party, that is, to stand for what the party stands for.
MPs whose ideal points are closer to the party median introduce more private member proposals.
Thus, as hypotheses 5 and 7 offer opposing predictions about the relationship between ideology and the propensity to offer proposals, it may be useful to clarify how the assumptions underlying the hypotheses differ. Hypothesis 5 can be seen as MPs prioritizing position-taking or the expressive value of making a proposal, whereas hypothesis 7 assumes that MPs take a more pragmatic view aimed at building the groundwork for advancing the policy, for example, by signaling its salience. The two hypotheses also relate to the importance of the parties in the legislature, with the latter hypothesis emphasizing that the parties play an important role in the policy-making process, that is, MPs are unlikely to succeed without the aid of their party.
Data & methods
Our empirical focus on is on the Icelandic Alþingi. Iceland has a multiparty system, where MPs are elected from party lists using a semi-open proportional representation system. Alþingi’s parliamentary procedures are permissive—the MPs face no formal restrictions when it comes to offering legislative proposals. Naturally, our arguments and findings may not easily travel to contexts where legislators face formal constraints, for example, in the form of cosponsorship requirements, that limit their ability to make legislative proposals. The lack of formal constraints, however, provides an opportunity to examine the basic incentives facing MPs in the absence of significant institutional constraints.
Another reason for considering Icelandic MPs is that while they are all elected using a semi-open list proportional representation system in districts, 5 some MPs earn their seats on their party list in primaries, while others depend on the party leadership for a position on the party list. Importantly, the use of primaries has varied across constituencies, and time, within most of the parties. 6
We collect information on bills and parliamentary motions introduced in Alþingi between 1991 (115 th session) and 2023 (153 rd ). During this period regular parliamentary sessions ran from mid-September or the start of October until mid-June. We exclude the short sessions that follow parliamentary elections from the analysis. As there was a change in government during 136 th session, we exclude the session as MPs cannot be easily classified as government or opposition MPs during the session. The unit of observation is the MP in each session. After removing ministers, who rarely propose private members’ bills and motions, this leaves us with a total of 554 MPs, 2298 private members’ bills, and 2857 parliamentary motions.
Our dependent variables are the number of private members’ bills and motions offered by each MP. Our independent variables include indicator variables for the MP’s primary participation, occupying a marginal seat on the party list, the MPs’ ideological divergence from their party and whether the MP represented a rural constituency. An MP is coded as having Contested Primary if they won their seat on the party list in a primary in the election prior to the parliamentary session (Indridason and Kristinsson, 2015). Last Seat In is coded 1 if the MP was the last MP to be elected from the party list in their constituency. Rural is coded 1 for constituencies other than those in the south-west corner (Reykjavík, Reykjanes, Suðvestur).
For measures of ideological distance, we follow Darmofal et al. (2025) and estimate WNOMINATE scores for each session. It must be noted that Alþingi is characterized by a high degree of party discipline, which poses a problem for ideal point estimation. The estimates are noisy, as one would expect, but they do capture some of the variance in the MPs’ ideological positions. However, it is important to keep these limitations in mind when interpreting the results.
The ideal point estimation suggests two ideological dimensions, socio-economic and urban-rural dimensions. While the first dimension reflects positions on the socio-economic dimensions to some degree, those estimates are heavily influenced by whether the MP is a member of a government or opposition party. We, thus, expect the NOMINATE scores on the first dimension to have limited relevance. Instead, we focus on the second dimension, and calculate the absolute value of the distance between the MP’s ideal point and their party’s median MP’s ideal point. Finally, we control for the MPs’ gender, age, and the number of days the MP sat in parliament during the session.
As our dependent variables are count variables of the number of bills and motions proposed by the MP, we estimate a mixed-effects negative binomial regression. We include fixed effects for the legislative session and party, and a random effect for the MP’s ideological distance from their party. As private members’ bills and parliamentary motions are expected to play different roles, we estimate separate models for bills and motions.
Results
Private members’ bills & parliamentary motions introduced—by government & opposition MPs.
Coefficients in bold indicate a statistically significant difference between government and opposition MPs (p < .05). See Appendix C.
***p < 0.01;**p < 0.05; *p < 0.1
In line with Hypothesis 1, government MPs introduce fewer private proposals than opposition MPs. 9 Government MPs are also more likely to propose motions than bills than opposition MPs are, suggesting that government MPs refrain from interfering with their party’s agenda by proposing bills as suggested by Hypothesis 2 (see Table G.10 in appendix). There is a slight indication that opposition MPs also prefer motions over bills, albeit to a lesser degree, but the effect ceases to be statistically significant once we control for other factors.
There is little evidence of electoral pressures driving MPs to offer proposals (Hypothesis 3). While government MPs elected through primaries appear to be more likely to offer motions, those that were last in their party list appear slightly less likely to offer either bills or motions (Hypothesis 4). 10
Ideological distance from the party median also has a limited effect. That said, among opposition MPs, the positive coefficient for ideological distance on bill proposals may indicate that MPs on the ideological fringes of their parties use private bills to signal their policy differences from the party. Similarly, albeit statistically insignificant, the positive effects for both bills and motions among government MPs imply that government MPs who are less aligned with their party may pursue private proposals as a way to express policy preferences that diverge from the party leadership’s agenda. These results are, at best, partly consistent with Hypothesis 5. There is nothing to suggest that the effect of ideology is strong for opposition MPs (Hypothesis 5-1). 11
Constituency considerations, however, appear to play a significant role. As conjectured in Hypothesis 6, representing a rural district is strongly and positively associated with bill introduction for both government and opposition MPs. Interestingly, rural representation has no effect on motion introduction. This suggests that constituency pressure pushes MPs toward bills rather than motions, regardless of whether they are in government or opposition. The contrast with our findings regarding electoral pressures is also interesting as contesting primaries only appeared to affect government MPs’ propensity to propose motions. The focus on proposing bills, rather than motions, and the low relevance of electoral pressures suggests, perhaps, that rural MPs seek tangible outcomes rather than simply signaling for the sake of building a personal vote.
For private members’ bills, notable differences emerge across gender and age groups for government and opposition MPs. Female government MPs are significantly less likely to propose bills, whereas gender has no meaningful effect for opposition MPs. A similar divergence appears for motions: opposition women are significantly more likely to introduce motions, while the corresponding coefficient is negative and insignificant for government MPs. Age effects mirror this pattern, with older opposition MPs introducing more bills, whereas older government MPs introduce fewer. With regard to age, these patterns are consistent with senior opposition MPs leading the charge against the government, whereas senior government MPs may be better socialized and more likely to fall in line with the government than their younger colleagues.
Additional result
We present some additional analysis in the online appendix. District magnitude may affect the importance of the personal vote. We find that government MPs are more likely to propose bills and motions in larger districts (Appendix D). In terms of ideology, the MP’s distance from the government policy may be more relevant than the MP’s distance from their party’s median. We find some indications that the MPs’ legislative behavior may be driven by considerations of the coalition’s policy (Appendix E). Finally, Appendix F reports the party effects, which show that the parties differ in terms of their party discipline (or cohesion).
Conclusions
Legislators in many parliamentary systems seek to present members’ bills and motions even when the odds of their passage are very slim, which raises questions about their motives. Legislators, however, are also expected to behave in a certain manner by their parties, and those expectations shape their behavior. We argue that those expectations differ in a systematic manner across government and opposition parties. Using information on all members’ bills and parliamentary motions proposed in Alþingi over three decades, we find mixed support for our conjectures. While MPs’ institutional position alone does not explain proposal behavior, party career incentives drive government MPs to propose significantly more motions than bills, to avoid interfering with the party’s agenda. Electoral pressure also mitigates party pressure, as government MPs from rural districts or facing contested primaries are more likely to make a private proposal despite their position in the government party. Ideological distance from the party median shows a suggestive association, with MPs who are more distant from their party median appearing to be more active in bill proposals, regardless of government status. The most robust finding is that both government and opposition rural MPs are significantly more likely to propose private members’ bills than those elected in urban districts, suggesting that constituency representation plays an important role for rural MPs, but also that such representation must take the form of actual legislation, as opposed to a less substantive parliamentary motion. Interestingly, female and older government MPs are less likely to propose bills, while that is not true of their counterparts in the opposition.
Supplemental material
Supplemental Material - Private members’ bills & parliamentary motions: Who bothers?
Supplemental Material for Private members’ bills & parliamentary motions: Who bothers? by Eunseong Oh, Indridi H. Indridason in Research & Politics
Footnotes
Acknowledgments
We are grateful to the reviewers and editor for their useful comments, as well as the current and former MPs who provided use with insights about the use of private members' bills in Iceland.
Funding
The authors received no financial support for the research, authorship, and/or publication of this article.
Declaration of conflicting interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Data Availability Statement
Data and replication code are available in the Research & Politics Dataverse (Indridason and Oh, 2026).
Carnegie Corporation of New York Grant
This publication was made possible (in part) by a grant from the Carnegie Corporation of New York. The statements made and views expressed are solely the responsibility of the author.
Supplemental material
Notes
References
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