O objetivo desta pesquisa foi avaliar a influência dos fatores culturais e institucionais do país de origem nas práticas contábeis utilizadas pelas empresas e, na sequência, analisar os impactos da existência de escolhas contábeis nas IFRS no nível de comparabilidade das informações contábeis de empresas localizadas em países com ambientes culturais e institucionais diferentes. A literatura sugere que a contabilidade é fortemente influenciada pelo ambiente no qual está inserida e que a comparabilidade é baseada no reflexo da substância econômica dos eventos, não na forma. Para tanto, foram analisadas três escolhas contábeis que existem ou existiam nas IFRS: (i) mensuração dos investimentos em joint ventures (consolidação proporcional ou MEP), (ii) reconhecimento e apresentação dos ganhos e perdas atuariais decorrentes dos planos de benefício definido (método do corredor, DRE ou DRA) e (iii) mensuração de PPI (custo ou valor justo). Os dados sobre as práticas contábeis foram coletados manualmente das demonstrações contábeis de 6.298 empresas de 27 países diferentes de 2005 até 2016. Portanto, foram coletadas e analisadas 53.908 demonstrações contábeis. Por meio da análise de cluster e utilizando um conjunto de variáveis culturais e institucionais, os 27 países foram classificados em 7 agrupamentos diferentes. Na sequência, foram avaliadas quais práticas contábeis predominavam em cada um desses países e como elas se relacionam com os agrupamentos formados e com as variáveis culturais e institucionais, através da estimação de modelos logísticos (hierárquicos na versão nula e não hierárquicos). Os resultados evidenciaram que uma parcela estatisticamente significante da variância das práticas contábeis é explicada pelo agrupamento de nível país e que todas as 12 variáveis culturais e institucionais são relevantes para explicar as práticas contábeis utilizadas pelas empresas em pelo menos uma das três escolhas contábeis analisadas. Por fim, utilizando a métrica de Comparabilidade dos Sistemas Contábeis desenvolvida por Barth et al. (2012), a presente pesquisa mensurou o nível de comparabilidade das informações contábeis entre as diversas combinações de clusters, com a finalidade de avaliar se as empresas eram mais comparáveis quando usavam exatamente a mesma prática contábil ou quando utilizavam práticas contábeis diferentes. Os resultados corroboram a tese proposta de que a existência de escolhas contábeis nas IFRS pode ser necessária para que as empresas utilizem as práticas contábeis que melhor refletem a substância econômica dos eventos, considerando a influência do ambiente cultural e institucional em que estão inseridas. Foram encontrados indícios de que a eliminação de escolhas contábeis, como a dos investimentos em joint ventures e de benefícios a empregados, pode reduzir a comparabilidade das informações contábeis, já que as empresas eram mais comparáveis quando utilizavam práticas contábeis diferentes. Assim, há evidências de que a adoção de padrões contábeis mais flexíveis contribui para a obtenção da comparabilidade em países com ambientes diferentes, reiterando que a substância econômica é mais importante que a forma. A principal contribuição desta pesquisa é fornecer evidências de que a obrigatoriedade de utilização da mesma prática contábil por empresas localizadas em ambientes culturais e institucionais diferentes pode resultar em uniformidade, mas não em comparabilidade das informações contábeis. / The purpose of this research was to evaluate the influence of cultural and institutional environment of each country in the accounting practices used by firms and, subsequently, to analyze the impacts of the existence of accounting choices in the IFRS Standards on the comparability of accounting information between firms from countries with different cultural and institutional environments. The literature suggests that accounting is strongly influenced by the environment and that comparability is based on the reflection of the economic substance of events, not on the form. Therefore, three accounting choices that exist or existed in IFRS Standards were analyzed: (i) measurement of joint venture investments (proportionate consolidation or equity method); (ii) recognition and presentation of actuarial gains and losses arising from defined benefit plans (corridor method, income statements or other comprehensive income) and (iii) measurement of investment properties (cost or fair value). The accounting practices\' data were manually collected from the financial statements of 6,298 firms from 27 different countries, from 2005 to 2016. Thus, we collected and analyzed 53,908 financial statements. Using cluster analysis and a set of cultural and institutional variables, the 27 countries were classified into 7 different clusters. Further, we analyzed the accounting practices that prevailed in each country and in each cluster; and how these accounting practices are influenced by the cultural and institutional variables, through the estimation of logistic models (hierarchical in the null version and non-hierarchical). The results indicate that the variance in accounting practices explained by the country level grouping is statistically significant and that all the 12 cultural and institutional variables are relevant to explain the accounting practices used by firms in at least one of the three accounting choices that were analyzed. Finally, using the Accounting System Comparability metric proposed by Barth et al. (2012), we measured the degree of comparability of accounting information among various combinations of clusters, in order to evaluate whether firms were more comparable when they used exactly the same accounting practice or when they used different accounting practices. The results corroborate the proposed thesis that the existence of accounting choices in the IFRS Standards may be necessary to allow firms to use those accounting practices that better reflect the economic substance of events, given the influence of the cultural and institutional environment in which they operate. We found evidence that the elimination of accounting choices, such as the choices about joint venture investments and employee benefits, may reduce the comparability of accounting information, given that firms were more comparable when they used different accounting practices. Thus, there is evidence that the adoption of more flexible accounting standards contributes to improve comparability in countries with different environments, reiterating that the economic substance is more important than the form. The main contribution of this research is to provide evidence that the mandatory requirement of the same accounting practices by firms from different cultural and institutional environments may result in uniformity, but not in comparability of accounting information.

<p>Uppsatsen redogör för tre svenska klädföretags miljöredovisningar och hur dessa uppfyller de kvalitativa egenskaperna: begriplighet, relevans, tillförlitlighet och jämförbarhet. Dessa kvalitativa egenskaper ska enligt det internationella redovisningsorganet IASBs föreställningsram vara uppfyllda i de finansiella rapporterna som företagen lämnar. De tre klädföretag som vi har valt att undersöka har offentliggjort frivilliga miljöredovisningar. I dagsläget finns det inga lagkrav på hur frivilliga miljöredovisningar ska presenteras, däremot finns det olika rekommendationer. Vi menar att IASBs fyra kvalitativa egenskaper kan appliceras på frivilliga miljöredovisningar i syfte att säkerställa ett visst mått av kvalitet. I vår uppsats har vi därför med utgångspunkt ifrån såväl IASB, FAR/SRS och FEE definierat vilka kriterier som rimligen bör ingå i dessa egenskaper. Egenskaperna har även anpassats till att kunna tillämpas på den svenska klädbranschen.</p><p>Studien utfördes genom att vi först undersökte företagens miljöredovisningar varpå dessa analyserades utifrån det vi avser med de kvalitativa egenskaperna: begriplighet, relevans, tillförlitlighet och jämförbarhet. Vidare har vi genomfört intervjuer med de respektive företagens miljöansvarige för att slutligen göra en avstämning mellan miljöredovisningarna, vår analys och det företagen själva har uttalat sig om.</p><p>I undersökningen har vi kommit fram till att ingen av företagens miljöredovisningar kan anses ha god kvalitet då samtliga uppvisar brister i någon av de kvalitativa egenskaperna som vi har utgått ifrån. Begripligheten i de tre miljöredovisningarna kan sägas vara god medan det förekommer bristfälligheter i fråga om relevans, tillförlitlighet och jämförbarhet.</p> / <p>This dissertation examines three Swedish clothing manufacturer’s  environmental accountancy statements and how these satisfy the qualitative properties: intelligibility, relevance, reliability and comparability. These qualitative properties should, according to the International Accounting Standards Board’s (IASB) framework, be satisfied in the companies’ published financial reports. The three clothing companies we chose to investigate have made public their voluntary environmental accountancy statements. There is currently no law stating how voluntary environmental accountancy statements are to be presented, though there are some recommendations. We consider that IASB’s four qualitative properties can be applied to voluntary environmental accountancy in order to guarantee a certain level of quality. We have therefore in this dissertation defined which criteria should be included in these properties on the basis of IASB, FAR/SRS and FEE. These properties have been modified to enable application within the Swedish clothing industry.</p><p>The study commenced with an investigation of the companies’ environmental accountancy statements. These were then analysed on the basis of what we consider to be the qualitative properties intelligibility, relevance, reliability and comparability. We furthermore conducted interviews with the environmental officer of each company; and finally compared the different environmental accountancy statements, our analyses and information obtained directly from each company.</p><p>In our study we concluded that none of the companies had environmental accountancy statements of good quality, as all had shortfalls in the qualitative properties which our study was based upon. Intelligibility in the three environmental accountancy statements can be described as good; however there were insufficiencies in the case of relevance, reliability and comparability.</p>

Uppsatsen redogör för tre svenska klädföretags miljöredovisningar och hur dessa uppfyller de kvalitativa egenskaperna: begriplighet, relevans, tillförlitlighet och jämförbarhet. Dessa kvalitativa egenskaper ska enligt det internationella redovisningsorganet IASBs föreställningsram vara uppfyllda i de finansiella rapporterna som företagen lämnar. De tre klädföretag som vi har valt att undersöka har offentliggjort frivilliga miljöredovisningar. I dagsläget finns det inga lagkrav på hur frivilliga miljöredovisningar ska presenteras, däremot finns det olika rekommendationer. Vi menar att IASBs fyra kvalitativa egenskaper kan appliceras på frivilliga miljöredovisningar i syfte att säkerställa ett visst mått av kvalitet. I vår uppsats har vi därför med utgångspunkt ifrån såväl IASB, FAR/SRS och FEE definierat vilka kriterier som rimligen bör ingå i dessa egenskaper. Egenskaperna har även anpassats till att kunna tillämpas på den svenska klädbranschen. Studien utfördes genom att vi först undersökte företagens miljöredovisningar varpå dessa analyserades utifrån det vi avser med de kvalitativa egenskaperna: begriplighet, relevans, tillförlitlighet och jämförbarhet. Vidare har vi genomfört intervjuer med de respektive företagens miljöansvarige för att slutligen göra en avstämning mellan miljöredovisningarna, vår analys och det företagen själva har uttalat sig om. I undersökningen har vi kommit fram till att ingen av företagens miljöredovisningar kan anses ha god kvalitet då samtliga uppvisar brister i någon av de kvalitativa egenskaperna som vi har utgått ifrån. Begripligheten i de tre miljöredovisningarna kan sägas vara god medan det förekommer bristfälligheter i fråga om relevans, tillförlitlighet och jämförbarhet. / This dissertation examines three Swedish clothing manufacturer’s  environmental accountancy statements and how these satisfy the qualitative properties: intelligibility, relevance, reliability and comparability. These qualitative properties should, according to the International Accounting Standards Board’s (IASB) framework, be satisfied in the companies’ published financial reports. The three clothing companies we chose to investigate have made public their voluntary environmental accountancy statements. There is currently no law stating how voluntary environmental accountancy statements are to be presented, though there are some recommendations. We consider that IASB’s four qualitative properties can be applied to voluntary environmental accountancy in order to guarantee a certain level of quality. We have therefore in this dissertation defined which criteria should be included in these properties on the basis of IASB, FAR/SRS and FEE. These properties have been modified to enable application within the Swedish clothing industry. The study commenced with an investigation of the companies’ environmental accountancy statements. These were then analysed on the basis of what we consider to be the qualitative properties intelligibility, relevance, reliability and comparability. We furthermore conducted interviews with the environmental officer of each company; and finally compared the different environmental accountancy statements, our analyses and information obtained directly from each company. In our study we concluded that none of the companies had environmental accountancy statements of good quality, as all had shortfalls in the qualitative properties which our study was based upon. Intelligibility in the three environmental accountancy statements can be described as good; however there were insufficiencies in the case of relevance, reliability and comparability.

Many graphs arising in practice can be represented in a concise and intuitive way that conveys their structure. For example: A planar graph can be represented in the plane with points for vertices and non-crossing curves for edges. An interval graph can be represented on the real line with intervals for vertices and intersection of intervals representing edges. The concept of ``simultaneity'' applies for several types of graphs: the idea is to find representations for two graphs that share some common vertices and edges, and ensure that the common vertices and edges are represented the same way. Simultaneous representation problems arise in any situation where two related graphs should be represented consistently. A main instance is for temporal relationships, where an old graph and a new graph share some common parts. Pairs of related graphs arise in many other situations. For example, two social networks that share some members; two schedules that share some events, overlap graphs of DNA fragments of two similar organisms, circuit graphs of two adjacent layers on a computer chip etc. In this thesis, we study the simultaneous representation problem for several graph classes. For planar graphs the problem is defined as follows. Let G1 and G2 be two graphs sharing some vertices and edges. The simultaneous planar embedding problem asks whether there exist planar embeddings (or drawings) for G1 and G2 such that every vertex shared by the two graphs is mapped to the same point and every shared edge is mapped to the same curve in both embeddings. Over the last few years there has been a lot of work on simultaneous planar embeddings, which have been called `simultaneous embeddings with fixed edges'. A major open question is whether simultaneous planarity for two graphs can be tested in polynomial time. We give a linear-time algorithm for testing the simultaneous planarity of any two graphs that share a 2-connected subgraph. Our algorithm also extends to the case of k planar graphs, where each vertex [edge] is either common to all graphs or belongs to exactly one of them. Next we introduce a new notion of simultaneity for intersection graph classes (interval graphs, chordal graphs etc.) and for comparability graphs. For interval graphs, the problem is defined as follows. Let G1 and G2 be two interval graphs sharing some vertices I and the edges induced by I. G1 and G2 are said to be `simultaneous interval graphs' if there exist interval representations of G1 and G2 such that any vertex of I is assigned to the same interval in both the representations. The `simultaneous representation problem' for interval graphs asks whether G1 and G2 are simultaneous interval graphs. The problem is defined in a similar way for other intersection graph classes. For comparability graphs and any intersection graph class, we show that the simultaneous representation problem for the graph class is equivalent to a graph augmentation problem: given graphs G1 and G2, sharing vertices I and the corresponding induced edges, do there exist edges E' between G1-I and G2-I such that the graph G1 U G_2 U E' belongs to the graph class. This equivalence implies that the simultaneous representation problem is closely related to other well-studied classes in the literature, namely, sandwich graphs and probe graphs. We give efficient algorithms for solving the simultaneous representation problem for interval graphs, chordal graphs, comparability graphs and permutation graphs. Further, our algorithms for comparability and permutation graphs solve a more general version of the problem when there are multiple graphs, any two of which share the same common graph. This version of the problem also generalizes probe graphs.

Bakgrund och problem: IAS 19 genomgår en ny förändring då en av redovisningsmetoderna för aktuariella vinster och förluster avskaffas. Korridormetoden, som fungerar som en utjämningsmekanism är den mest frekvent tillämpade metoden av stora börsnoterade bolag i Sverige. Avskaffningen av metoden väntas få effekter på dessa företags finansiella ställning då företag 2013 kommer tvingas ta fram sina oredovisade aktuariella förluster och redovisa dessa i sin helhet. Syfte: Syftet med uppsatsen är att studera berörda aktörers uppfattning om nya IAS 19 som träder i kraft 2013 samt vilken påverkan den förväntas ha på börsnoterade företag som idag tillämpar korridormetoden. Metod: Genom intervjuer inhämtade vi material av kvalitativ natur. Data av denna karaktär är bäst lämpad för vår studie då vi vill undersöka inställningar till en förändring som ännu inte har trätt i kraft och som kommer beröra företags finansiella rapportering. Resultat och slutsats: Kritiken från två av de tillfrågade gällande korridormetoden rör inte den utjämningsmekanism som finns, utan snarare att metoden inte har genomfört sitt syfte som man upptäckt på senare år.  Detta har i sin tur lett till att företag samlat på sig stora aktuariella förluster i samband med sina pensionsåtaganden. Då IAS 19 har krävt flera omarbetningar och den senaste modifieringen av standarden kan ses som en tillfällig lösning tills att man kommer fram till en metod som speglar skulden på ett mer korrekt sätt. Borttagandet av korridormetoden har enligt respondenterna fler fördelar än nackdelar vilket för pensionsredovisningen vidare i utvecklingen. Dock medger alla respondenter att komplexiteten fortfarande är för bred för att IAS 19 inte ska kräva ännu mera omarbetning. Vi ser ännu inte att problemen med pensionsredovisningen är nära att nå sitt slut. Respondenternas attityder kring problemet är att en förenkling eftersträvas men vägledning som leder till lösning på problemet är ännu mer avlägset. Ingen av våra respondenter har framfört att borttagandet av korridormetoden är självaste lösningen på problemet. Förslag till vidare forskning: Vi skulle tycka det vore intressant om man undersökte efter övergången till en av de andra två metoderna för att mäta de effekter som slopandet av korridormetoden medförde. Hur stora aktuariella förluster fick företag inom Large Cap? / Background to problem: IAS 19, is undergoing a new change when one of the accounting methods to actuarial gains and losses is eliminated. The corridor method, which acts as a clearing mechanism is the most frequently applied method of large listed companies. Abolishment of the method is expected to have an impact on their financial position starting in the year 2013. Companies are forced to report its unrecognized actuarial losses and account these entirely. Purpose: The purpose of this thesis is to study the actors' perception of the new IAS 19 which comes into force in 2013 and the expected impact on the large listed companies applying the corridor method at present. Methodology: We acquired materials of a qualitative nature through interviews. Data of this nature is best suited for our study because we want to examine the settings for a change that has not yet entered into force and is expected to affect the company’s financial reporting. Conclusions: The criticism from two of the surveyed does not concern the meaning of the standard IAS 19 parse, but rather that the method has not fulfilled its purpose as exposed in recent years. This has in turn led to accumulated actuarial losses related to its pension commitments.IAS 19 has required several revisions, and the latest modification of the standard can be viewed as a temporary solution until a method that reflects the debt in a more accurate way is achieved. Removal of the corridor method, according to respondents, has more advantages than disadvantages which leads the pension accounting further in development. However, all respondents admit that the complexity is still too wide for IAS 19, and will require more adjustments. We do not see that the problems with pension accounting are close to reaching its end. Respondents' attitudes to the problem are that the simplification is needed, but guidance that leads to the solution of the problem is even more remote. None of our respondents have said that the removal of the corridor approach is the solution to the major problem of pension accounting. Suggestions for further research: We would find it interesting if a study is made after the transition to one of the other two methods, measuring the impact of the abolition of the corridor approach. How large actuarial losses were companies in the large-cap hit of?

本論文主要係立基於Milkovich & Newman所提出的「待遇管理的基本決策理論」，以呈現待遇管理最重要的目的之一，就是求得公平，並透過待遇公平性理論的探討，將焦點集中在維繫待遇外在公平性的作法（實施民間薪資調查）上。再套用菁英決策理論與團體理論，據以選擇與我國同樣是採取高度中央集權且由專業主管機關主導公務人員待遇調整的國家（例如美、日及新加坡）作為比較研究對象。其主要目的是參酌美、日及新加坡等國政府在公務人員待遇調整上運用比較原則之作法與經驗，以針對現行我國公務人員待遇調整機制之實務作業，提出下列改進建議： 一、將比較原則作為決定我國公務人員待遇調整幅度之重要參考指標，並以法律規範之。 二、待遇調整時，可思考選擇加重分配各項加給、津貼之調整比重。 三、提升我國民間企業薪資調查之周全度。 四、進行公、私部門關鍵性員工待遇水準比較之方法應更細緻化。 五、公私部門員工待遇之比較改由客觀而具權威的第三者機構進行。

Cette thèse porte sur les fondations de la théorie des préférences et de l'utilité utilisée dans les domaines du choix social et de la théorie de la décision. Le premier chapitre est l'introduction. Le second chapitre est composé d'une revue de la littérature et des résultats existants, d'une discussion des motivations pour envisager un nouveau cadre théorique permettant de combiner différentes approches de l'agrégation des préférences individuelles, et d'une proposition d'un modèle hybride appelé modèle de préférence-approbation. Le troisième chapitre pose la question du sens que l'on peut donner au consensus dans un tel cadre théorique. Pour y répondre, ce travail fournit une approche basée sur la notion de distance, c'est-à-dire d'une métrique définie sur le domaine des préférence-approbations, et examine différentes façons de mesurer l'homogénéité au sein d'un ensemble d'opinions individuelles. Dans cette nouvelle modélisation des opinions, les individus s'expriment à la fois à travers un classement défini sur l'ensemble des alternatives et par un niveau de seuil, permettant de distinguer dans ce classement les alternatives "approuvées" de celles qui sont "désapprouvées". Le quatrième chapitre comporte une analyse de la manipulabilité des règles d'agrégation définies sur un profil de votes composés de classements et d'évaluations binaires. En introduisant une nouvelle notion de non-manipulabilité, cette étude offre un résultat de possibilité, ainsi que certaines caractérisations d'impossibilités. La conclusion permet de discuter plusieurs questions de recherche future sur la manière de définir de nouveaux systèmes d'élections et mécanismes de votes, ainsi que leurs impacts potentiels sur la société.

Globalization has led to the growth of international financial markets, as one of the results, the EU adopted IFRS in 2005 to meet the need of accounting globalization and harmonization. This action has triggered a debate about whether the adoption of IFRS is beneficial to accounting quality and information comparability. Meanwhile, China, playing a key role in the global economic development stage, realizes the importance of accounting harmonization and attempts to move towards the IFRS as well. However, to reach the goal that the Chinese companies produce financial statements that are the same as those that apply IFRS, there is still a long way to go. The purpose of this thesis is to examine whether the adoption of IFRS by EU has enhanced the quality of financial reporting and accounting information comparability. Additionally, the thesis further identified the seminal undertakings for the convergence of IFRS in Europe and pointed out the implication for China’s convergence with IFRS. The empirical findings in this thesis were obtained through qualitative interviews. The empirical findings suggest that accounting quality and information comparability has been enhanced with EU’s strong and full enforcement with IFRS. With the confidence in IFRS which is gained from the success of the EU’s adoption of IFRS, a coherent result was found that the convergence towards IFRS would also benefit China in accounting quality and information comparability, and further lead to more international investments. However, when it comes to the question whether China should emulate EU’s example to adopt IFRS directly or keep CAS (Chinese Accounting Standards) which is similar to IFRS, two mixed opinions were obtained basically from Europe side and China side. Through in-depth analysis with these empirical findings, the conclusion is that it is necessary for China to take steps to build intensive programs to enhance its capacity of the adoption of IFRS, so that it could adapt itself to the fact that the IFRS is already making its way around the world as a single set of high quality global accounting standards.

Park and resource management agencies are looking for less costly ways to undertake park visitor surveys. The use of the Internet is often suggested as a way to reduce the costs of these surveys. By itself, however, the use of the Internet for park visitor surveys faces a number of methodological challenges that include the potential for coverage error, sampling difficulties and nonresponse error. A potential way of addressing these challenges is the use of a mixed-mode approach that combines the use of the Internet with another survey mode. The procedures for such a mixed-mode approach, however, have not been fully developed and evaluated. This study develops and evaluates a new mixed-mode approach –a face-to-face/web response – for a provincial park camper survey in British Columbia. The five key steps of this approach are: (a) selecting a random sample of occupied campsites; (b) undertaking a short interview with potential respondents; (c) obtaining an email address at the end of the interview; (d) distributing a postcard to potential respondents that contains the website and an individual access code; and (e) undertaking email follow-ups with nonrespondents. In evaluating this new approach, two experiments were conducted during the summer of 2010. The first experiment was conducted at Goldstream Provincial Park campground and was designed to compare a face-to-face/paper response to face-to-face/web response for several sources of survey errors and costs. The second experiment was conducted at 12 provincial park campgrounds throughout British Columbia and was designed to examine the potential for coverage error and the effect of a number of email follow-ups on return rates, nonresponse error and the substantive results. Taken together, these experiments indicate: a low potential for coverage error (i.e., 4% non-use Internet rate); a high email collection rate for follow-ups (i.e., 99% at Goldstream; a combined rate of 88% for 12 campgrounds); similar return rates between a paper mode (60%) and a web (59%) mode; the use of two email follow-ups reduced nonresponse error for a key variable (i.e., geographic location of residence), but not for all variables; low item nonresponse for both mixed-modes (about 1%); very few differences in the substantive results between each follow-up; a 9% cost saving for the web mode. This study suggests that a face-to face/web approach can provide a viable approach for undertaking park visitor surveys if there is high Internet coverage among park visitors. / Graduate / 0366 / 0344 / 0814 / brdyckfam@yahoo.com

Many graphs arising in practice can be represented in a concise and intuitive way that conveys their structure. For example: A planar graph can be represented in the plane with points for vertices and non-crossing curves for edges. An interval graph can be represented on the real line with intervals for vertices and intersection of intervals representing edges. The concept of ``simultaneity'' applies for several types of graphs: the idea is to find representations for two graphs that share some common vertices and edges, and ensure that the common vertices and edges are represented the same way. Simultaneous representation problems arise in any situation where two related graphs should be represented consistently. A main instance is for temporal relationships, where an old graph and a new graph share some common parts. Pairs of related graphs arise in many other situations. For example, two social networks that share some members; two schedules that share some events, overlap graphs of DNA fragments of two similar organisms, circuit graphs of two adjacent layers on a computer chip etc. In this thesis, we study the simultaneous representation problem for several graph classes. For planar graphs the problem is defined as follows. Let G1 and G2 be two graphs sharing some vertices and edges. The simultaneous planar embedding problem asks whether there exist planar embeddings (or drawings) for G1 and G2 such that every vertex shared by the two graphs is mapped to the same point and every shared edge is mapped to the same curve in both embeddings. Over the last few years there has been a lot of work on simultaneous planar embeddings, which have been called `simultaneous embeddings with fixed edges'. A major open question is whether simultaneous planarity for two graphs can be tested in polynomial time. We give a linear-time algorithm for testing the simultaneous planarity of any two graphs that share a 2-connected subgraph. Our algorithm also extends to the case of k planar graphs, where each vertex [edge] is either common to all graphs or belongs to exactly one of them. Next we introduce a new notion of simultaneity for intersection graph classes (interval graphs, chordal graphs etc.) and for comparability graphs. For interval graphs, the problem is defined as follows. Let G1 and G2 be two interval graphs sharing some vertices I and the edges induced by I. G1 and G2 are said to be `simultaneous interval graphs' if there exist interval representations of G1 and G2 such that any vertex of I is assigned to the same interval in both the representations. The `simultaneous representation problem' for interval graphs asks whether G1 and G2 are simultaneous interval graphs. The problem is defined in a similar way for other intersection graph classes. For comparability graphs and any intersection graph class, we show that the simultaneous representation problem for the graph class is equivalent to a graph augmentation problem: given graphs G1 and G2, sharing vertices I and the corresponding induced edges, do there exist edges E' between G1-I and G2-I such that the graph G1 U G_2 U E' belongs to the graph class. This equivalence implies that the simultaneous representation problem is closely related to other well-studied classes in the literature, namely, sandwich graphs and probe graphs. We give efficient algorithms for solving the simultaneous representation problem for interval graphs, chordal graphs, comparability graphs and permutation graphs. Further, our algorithms for comparability and permutation graphs solve a more general version of the problem when there are multiple graphs, any two of which share the same common graph. This version of the problem also generalizes probe graphs.