| Study | Time distribution | Type of test | Results |
| McKee (1983) | Intensive French: 120 h; 25 h/week Traditional: 120 h; 4 h/week | Listening Reading Writing (controlled and free) Questionnaire | Intensive higher than traditional but not significantly in listening, controlled writing and reading Intensive significantly better in free writing Intensive more eager to use target language and more motivated |
| Spada and Lightbown (1989) | Intensive English: 350 - 400 h in 5 months “Drip-feed” traditional: 70 h/10 months | Baldwin-Cartier Test de classement (BTC) MEQ listening comprehension Picture card game (oral skills) | Intensive students superior to traditional at their level in all tasks and at higher levels with same instruction hours in listening and reading Intensive learners more fluent and confident |
| Lightbown and Spada (1994) | Intensive English: 350 - 400 h/school year; 18 - 20 h/week Traditional: max. 70 h/year; 2 h/week | Listening Reading Speaking Delayed-posttest (interview, communicative task and questionnaire) | Intensive students superior to traditional at their level in all tasks and at higher levels with same instruction hours in listening and reading Superiority maintained in delayed posttest |
| Lapkin et al. (1998) | Drip-feed French Second Language model (40 min/day in 10 months) Half-day compact model (half day French instruction for 10 weeks) 80-min/day for 5 months | Prepost French test including listening, reading, writing, speaking Follow-up test: reading, writing Students’ and parents’ questionnaires | More advantages for half-day compact model, then 80-min (in reading) Gains maintained in follow-up test Students in compact models reported more improvement in learning French, but also some boredom and reduction of attention span |
| Collons et al. (1999) | Massed English: 350 - 400 h in 5 months Massed plus: same as massed plus extra activities in English Distributed: 350 - 400 h in 10 months | Vocabulary recognition MEQ: emphasis on listening comprehension but also reading Narrative: describing pictures orally | Students in massed and massed plus performed better in all tasks than in distributed |
| Peters (2000) | Intensive French: 350 - 400 h/year; 18 - 20 h/week Traditional: 120 h/year; max 4 h/week | Interviews Listening Speaking Reading Writing | More gains on the part of intensive learners More self-confidence for intensive learners |
| MacFarlane et al. (2004) | Intensive French: 350 - 400 h/year; 18 - 20 h/week Traditional: 120 h/year; max 4 h/week | Interviews | Students in intensive programs more self-confidence and positive attitudes towards learning French |
| Freed et al. (2004) | Traditional French: 2 - 4 h/week Intensive French: 17.5 h/week (plus out-of-class contact) Study Abroad in France: 16.4 h/week (plus out-of-class contact) | Recorded interviews (to analyze oral fluency) Out-of-class contact questionnaire (use of French outside of class | Intensive students more significant gains in most measures of fluency than other two groups Intensive students reported higher use of French outside the class |
| White and Turner (2005) | Intensive English: 350 - 400 h/school year; 18 - 20 h/week Traditional: max 35 - 70 h/year; 1 h/week | Oral ability Audio-Pal Story Retell Info-Gap | Intensive students gained significantly more than those in traditional classes |
| Hinger (2006) | Regular Spanish classes: 48 h in one semester, 2.5 h/week Intensive: 48 h in 1 month, 12 h/week | Recordings of verbal behavior during class | Students in intensive group had more group cohesion and were more motivated |
| Serrano (2007) | Extensive: 110 h/7 months, 4 h/week Semi-intensive: 110 h/3 - 4 months, 8 - 10 h/week Intensive: 110/5 week, 25 h/week | Sentence Cloze Listening Writing | Students registered in extensive classes make less progress in a 110 h course than those in intensive groups (both semi-intensive and intensive) |
| Serrano (2011) | Regular course: 110 h in one year, twice per week, 2 h at a time Intensive course: 110 h in one year, 5 days/week, 5 h at a time | Proficiency test Written task Oral narrative | intermediate-level students tend to make more language gains in intensive programs than in regular programs, whereas advanced EFL students do not seem to benefit from intensive classroom practice as much as intermediate students do |
| Rogers (2015) | Massed group: in 5 consecutive lessons (Sunday, Tuesday, Thursday, Sunday, Tuesday), 2.25 days between each training session Distributed group: once a week, on Tuesdays, for 5 consecutive weeks | Yes/No comprehension check question | when the results were measured on immediate posttests, there is no significant difference between massed (intensive) and distributed (extensive) conditions in improving learners’ L2 grammar When measured on 6-week delayed posttests, students in distributed group significantly outperformed the massed group |