This doctoral thesis has been carried out at the University of León as part of the Doctoral Programme in Educational Psychology and Educational Sciences, regulated by Royal Decree 576/2023, of 4 July, which amends Royal Decree 99/2011, of 28 January; Royal Decree 1002/2010, of 5 August; and Royal Decree 641/2021, of 27 July. In accordance with the stipulations of these regulations, the Doctoral Programme establishes the obligation to carry out different training activities focused on optimising the research training of doctoral students. These activities, specifically in the aforementioned doctoral programme, are related to aspects such as participation in academic seminars for doctoral students, meetings with thesis supervisors and with the research group, the presentation of papers at international conferences and conferences for doctoral students, the carrying out of scientific management and assessment processes, as well as other complementary activities such as, for example, attendance at training courses. Specifically, for the presentation format followed in this doctoral thesis, by compendium of publications and international mention, the Doctoral Programme requires two additional activities to be carried out.
The first activity consists of obtaining international thesis recognition, for which it is necessary to carry out one or more research stays in foreign universities for a minimum period of three months. Furthermore, according to the regulations, in the case of several stays, at least one of them must have a minimum duration of one month. Specifically, two stays were carried out for this doctoral thesis. The first, lasting one month, took place at the University of Utrecht, under the supervision of Dr. Huub van den Bergh between April and May 2023. The second stay lasted two months, from February to April 2024, and was carried out at the University of Porto under the supervision of Dr. Rui Alexandre Alves. Both research stays have undoubtedly contributed to the development of the research presented in the doctoral thesis. In order to carry out these research stays, support was requested from the Programa Propio de Ayudas a la Investigación de la Universidad de León (University of León Research Grants Programme).
The second activity, which is compulsory for passing the Doctoral Programme, involves the publication of at least three research articles, at least one of which must be published in a journal.

indexed in the Journal Citation Report (JCR) or in quartiles 1 or 2 of the SCImago Journal & Country Rank (SJR). The rest of the scientific publications that make up the doctoral thesis may be published in any journal included in JCR, SJR, SCOPUS, Dialnet Metrics (within quartiles 1 and 2) or in the list of Spanish scientific journals with the FECYT Seal of Quality. Likewise, publications included in the Scholarly Publishers Indicators (SPI) within the field of Humanities and Social Sciences that are in quartile 1 at a national level or in quartile 1 and 2 of the Education or Psychology sectors at an international level are also accepted. In this sense, the present doctoral thesis is composed of five publications, three of which have already been published and meet the aforementioned criteria. On the one hand, Study 1 (chapter 4) of the thesis has been published in the journal Sustainability indexed in both JCR and SJR with a Q2 quartile. On the other hand, Studies 2 and 4 (chapter 4) were published in book chapter format in the Dykinson S.L. publishing house, which has a Q1 quartile in the Education SPI. These indexing requirements have allowed the doctoral thesis to be presented and defended as a compendium of publications.
The thesis is part of the research line on the teaching of written composition and is directed by Dr. Raquel Fidalgo (University of León), Dr. Paula López (University of León) and Dr. Gert Rijlaarsdam (University of Amsterdam). Specifically, the research work carried out in the thesis focuses on analysing the teaching of written composition through the use of Information and Communication Technologies (ICT) from two perspectives. Firstly, the compositional analysis of different writing interventions carried out with ICT is approached on the basis of their content dimension and their instructional dimension, also analysing the influence of the different instructional elements of the intervention on the size of the effect of the intervention. Secondly, we analyse teachers' use of ICT for teaching writing and the influence of different teacher modulating variables on the frequency of ICT use. This research has been possible thanks to the support of the project with reference TED2021-13647B-I00, funded by the MCIN/AEI/10.13039/501100011033 and by the European Union "NextGenerationEU/PRTR", and by the Junta de Castilla y León through the granting of a pre-doctoral scholarship to the PhD student (ORDEN EDU/875/2021, 13 July).

Based on the regulations established by the University of León for the publication of doctoral theses in the form of a compendium of publications, the thesis is structured in five main sections. These sections are: introduction, objectives, method, results and conclusions.
In the first introductory section (chapter 1), the theoretical and empirical foundations on which the studies that make up the doctoral thesis are based are presented. Although each study presents a theoretical justification, in this first chapter the theory is presented in a general way in order to show the context in which the research work carried out during the PhD is framed. Thus, the theory is presented in three complementary sections. The first shows a brief theoretical foundation of writing competence from a psychological perspective, addressing both its conceptualisation and the processes that comprise it on the basis of different theoretical models. The second section presents the state of the art in the use of ICT for teaching writing competence, describing its importance in today's society and showing the scientific advances made in recent years based on the results found in previous review studies and meta-analyses. In the last section, a review of possible modulating teaching variables that may influence the use of ICT, which may be applicable to the teaching of writing, is presented.
In the second section (chapter 2), the objectives of the doctoral thesis are presented in detail. It also shows the relationship of these objectives with the studies that make up the doctoral thesis, offering a brief description of them together with their reference in APA format and the quality indicators of the journal or book in which they have been published.
The third section (chapter 3) shows the methodology followed in each of the studies of the doctoral thesis, showing again the relationship of these studies with the objectives of the thesis. Specifically, the design, type of research, coding process and types of statistical analysis carried out in each study are indicated in a synthesised form. It should be noted that the studies that presented the same methodological design (e.g., empirical review studies) are shown in a grouped form, in order to avoid repetitions in the content of the chapter and to facilitate the understanding of the procedure carried out.

The fourth section (Chapter 4) consists of the presentation of the results of the doctoral thesis which, in accordance with the publication compendium modality, correspond to the presentation of the articles that constitute the doctoral thesis. The first study published in the journal Sustainability (Q2 in JCR and SJR), follows a review methodology and focuses on compositionally analysing different instructional practices of writing with ICT based on their content (what is taught) and instructional (how it is taught) dimensions. The second study, which also follows a review methodology, was published in book chapter format by Dykinson S.L. (publisher indexed in the SPI of Education with Q1) and focuses on the analysis of different writing instructional practices with and without ICT aimed at improving the writing competence of students at risk of social deprivation (i.e., with low socio-economic status). The third study of the thesis is currently under review for publication in the journal Educational Research Review (Q1 in JCR and SJR) and consists of a meta-analysis whose aim is to analyse componentially different writing instructional practices with ICT to improve students' writing proficiency based on different instructional elements, as well as to analyse the effect size of these interventions and the influence that the instructional components and the agent through which they are delivered play in the greater or lesser effect size. The fourth study was published by Dykinson S.L. (publisher indexed in the SPI of Education with Q1) as a book chapter and consists of an empirical review in which the variables that affect the use of ICT in the classroom by Primary and Compulsory Secondary Education teachers were analysed. The last study of the thesis follows a survey methodology and focuses on analysing the use of ICT by Compulsory Education teachers of Spanish Language and Literature to teach writing skills, as well as the relationship between teacher modulating variables and the frequency of ICT use. The latter study is currently under review for publication in the journal Comunicar (Q1 in JCR and SJR).
Finally, in accordance with the regulations of the University of León regarding the presentation of doctoral theses with international mention, the conclusions are presented in Spanish (chapter 5) and in English (chapter 6). Although the specific conclusions are presented in each of the publications that make up the doctoral thesis, these sections show the overall conclusions of the thesis.

conclusions obtained from the results of the thesis. It also presents the limitations, the lines of future research and the scientific and educational contributions derived from the thesis.