Exequiel Gonzalez Cynthia Lara Online performance-based assessment instruments I. Online performance- based assessment instrument to assess Grammar. English 4 U is a web page where we could find different explanations about grammar, exercises and online quizzes to assess vocabulary and grammar. This web page offers different online grammar exercises and online quizzes which are divided into topics. Most of the online grammar exercises, depending on the exercise, are about filling the gaps, completion and unscramble sentences. Most of the quizzes in this page are design to assess vocabulary. The page is colorful and the exercises and quizzes are for Beginner to elementary level ESL/EFL students. We will only analyze one part of this web page, which is the one to assess grammar, in order to know the pros and cons of using this page to assess this system of the language. The pros of using this web page to assess grammar have relation with some principles such as: Practicality: The activities, exercises and quizzes related to grammar are online which makes it not expensive to be administered or used, it is easy to use, because it does not need the use of any extra application, but just some clicks to start doing the exercises. It is time efficient, because it doesn't take too much time for students to do the activities or quizzes and they are checked automatically. Reliability: The activities, exercise and quizzes are not long and they are designed in such way that they could be done at any time by students and get similar results. Validity: The exercises and quizzes assess what was taught in the topic. The cons of using this web page to assess grammar have relation with some principles such as: Authenticity: The activities, exercises and quizzes lack of authenticity as they don't simulate real world situation and students are not expected to use what they read, but only to write the right answer. Transparency: There is not clear information about weighting of items and sections, time allowed to complete the test or exercises and grading criteria. Washback: It is not appropriately provided, because students receive just a score or something saying that what they answered is good or wrong. II. Online performance- based assessment instrument to assess Vocabulary. a4esl.org It is a web page where you can find different topics to assess vocabulary., exercises and online quizzes to assess vocabulary and grammar. The page offers a variety of topics, it shows pictures and give alternatives to answer. The page is not so colorful and maybe it won’t be very attractive for students the quizzes are for Beginner to elementary level ESL/EFL students. The pros of using this web page to assess vocabulary have relation with some principles such as: Practicality: The activities are very easy to check because the page offers an automatic correction which makes it not expensive to be administered or used, it is very easy and does not need any explanation Validity: The exercises and quizzes assess what was taught in the topic. The cons of using this web page to assess grammar have relation with some principles such as: Authenticity: The activities, exercises and quizzes lack of authenticity as they don't simulate real world situation and students are not expected to use what they read, but only to write the right answer. Transparency: There is not clear information about weighting of items and sections, time allowed to complete the test or exercises and grading criteria. Washback: It is not appropriately provided, because students receive just a score or something saying that what they answered is good or wrong Reliability: Low. The quizzes are not long and they are designed in such way that they could be done at any time by students and get similar results. The problem with assessing online is that students could revise other web pages in order to get the correct answers.