The descriptive study identified and analyzed the error categories of students in College Algebra in the Higher Education Institutions of La Union as basis for formulating a validated Instructional Intervention Plan. Specifically, it determined the a) level of performance of the students in College Algebra along elementary topics in sets and Venn diagrams, real numbers, algebraic expressions, and polynomials; special product patterns; factoring patterns; rational expression; linear equations in one unknown; systems of linear equations in two unknowns; and exponents and radicals; b) the capabilities and constraints of the students in College Algebra; and, c) the error categories of the students along reading, comprehension, mathematising, processing and encoding. Data were collected using a researcher-made, all-word-problem test. The participants were 374 first year students enrolled in College Algebra for first semester, school year 2013-2014. The data gathered were treated statistically using frequency count, mean, percentage and the Newmann’s tool for error analysis. It found out that the students had fair performance in elementary topics, special products and factoring while poor performance in rational expressions, linear equations and systems of linear equations and very poor performance in exponents and radicals; thus, the students, in general, had poor performance. The performances of the student in the specified topics were all considered as constraints. Mathematising and comprehension were the major error categories of the students in elementary topics, processing and reading errors in special products, reading and Mathematising in factoring, reading and Mathematising in rational expressions, reading and comprehension in linear equations; and reading and Mathematising in systems of linear equations and exponents and radicals. In general, their major error categories in College Algebra were along reading and Mathematising. Moreover, the instructional plan is
9. ix found to have very high validity. Based on the findings, it was concluded that the students cannot competently deal with elementary topics, special product and factoring patterns rational expressions, linear equations, systems of linear equations and radicals and exponents. Additionally, the instructional intervention plan is a very good material that addresses problems on performance and errors. Based on the conclusions, it is recommended that the schools should adopt the Instructional Intervention Plan and let their mathematics instructors attend the two-day seminar-workshop. The students should exert more effort in understanding the different concepts in their College Algebra course. They should spend more time dealing with drills and exercises. The mathematics teachers should suit their instructional strategies to the needs of the students. The English teachers must also intensify in their classes the basic skill of reading with comprehension. A study should be conducted to determine the effectiveness of the instructional intervention plan. And, a similar study should be conducted in other branches of Mathematics, applied sciences and English.