ÖE

Özkan Eren

University of California, Riverside

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i-10 index

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Naci Mocan

Louisiana State University

José L. Hierro

Universidad Nacional de La Pampa

Serkan Ozbeklik

Claremont McKenna College

Daniel Montesinos

University of Coimbra

Heather Antecol

Claremont McKenna College

Dean E. Pearson

Rocky Mountain Research (United States)

Yvette K. Ortega

Rocky Mountain Research Station

Diego Villarreal

Southwest Texas Junior College

Kris French

University of Wollongong

Lohengrin A. Cavieres

Institute of Ecology and Biodiversity

Cooperative Institutions

Universidad Nacional de La Pampa

University of Montana

Consejo Nacional de Investigaciones Científicas y Técnicas

American University of Armenia

Georgian National Academy of Sciences

National Bureau of Economic Research

Louisiana State University

University of Coimbra

California Department of Conservation

National Institute of Research and Development for Biological Sciences

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The effect of teacher gender on student achievement in primary school: Evidence from a randomized experiment

SSRN Electronic Journal (2012)

Heather Antecol Özkan Eren Serkan Ozbeklik

This paper attempts to reconcile the contradictory results found in the economics literature and the educational psychology literature with respect to the academic impact of gender dynamics in the classroom. Specifically, using data from a randomized experiment, we look at the effects of having a female teacher on the math test scores of students in primary school. We find that female students who were assigned to a female teacher without a strong math background suffered from lower math test scores at the end of the academic year. This negative effect however not only seems to disappear but it becomes (marginally) positive for female students who were assigned to a female teacher with a strong math background. Finally, we do not find any effect of having a female teacher on male students' test scores (math or reading) or female students' reading test scores. Taken together, our results tentatively suggest that the findings in these two streams of the literature are in fact consistent if one takes into account a teacher's academic background in math.

Randomized experiment

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Citations (6)

Lomelosia solymica (Dipsacaceae), a new chasmophyte from the Western Taurus Mts, Turkey

Willdenowia - Annals of the Botanic Garden and Botanical Museum Berlin-Dahlem (2005)

Gerald Parolly Özkan Eren Birgit Nordt

Parolly, G., Eren, Ö. & Nordt, B.: Lomelosia solymica (Dipsacaceae), a new chasmophyte from the Western Taurus Mts, Turkey. — Willdenowia 35: 107–115. — ISSN 0511-9618; © 2005 BGBM Berlin-Dahlem. doi:10.3372/wi.35.35108 (available via http://dx.doi.org/)Lomelosia solymica, a plant of montane, sea facing cliffs of the Tahtalı Dağı in the Western Taurus Mts south of Antalya is described as a species new to science and illustrated. Its isolated taxonomic position within the genus and its peculiarities, such as the awnless calyx, are discussed. We interpret the latter character within the chasmophytic syndrome and develop the hypothesis that it facilitates dispersal by ants into narrow rock fissures.

Willdenowia

Calyx

10.3372/wi.35.35108

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Citations (7)

The Effect of Grade Retention on Adult Crime: Evidence from a Test-Based Promotion Policy

SSRN Electronic Journal (2020)

Özkan Eren Michael Lovenheim Naci Mocan

This paper presents the first analysis in the literature of the effect of test-based grade retention on adult criminal convictions. We exploit math and English test cutoffs for promotion to ninth grade in Louisiana using administrative data on all public K-12 students combined with administrative data on all criminal convictions in the state.Our preferred model uses the promotion discontinuity as an instrument for grade retention, and we find that being retained in eighth grade has large long-run effects on the likelihood of being convicted of a crime by age 25 and on the number of criminal convictions by age 25. Effects are largest for violent crimes: the likelihood of being convicted increases by 1.05 percentage points, or 58.44%, when students are retained in eighth grade. Our data allow an examination of mechanisms, and we show that the effects are likely driven by declines in high school peer quality and educational investments that result in lower non-cognitive skill acquisition.We find little effect on juvenile crime. Using the method proposed by Angrist and Rokkanen (2015), we also estimate effects of grade retention away from the promotion cutoff and show that our results are generalizable to a larger group of low- performing students. Our estimates indicate that eighth grade test-based promotion cutoffs lead to nontrivial private and social costs in terms of higher levels of long-run criminal convictions that are important to consider in the development and use of these policies.

Promotion (chess)

Grade retention

10.2139/ssrn.3708632

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Citations (2)

Peer Review #3 of "Extensive analysis of native and non-native Centaurea solstitialis L. populations across the world shows no traces of polyploidization (v0.1)"

Ramona-Elena Irimia Daniel Montesinos Özkan Eren Christopher J. Lortie Kris French

Background.Centaurea solstitialis L. (yellow starthistle, Asteraceae) is a Eurasian native plant introduced as an exotic into North and South America, and Australia, where it is regarded as a noxious invasive.Changes in ploidy level have been found to be responsible for numerous plant biological invasions, as they are involved in trait shifts critical to invasive success, like increased growth rate and biomass, longer life-span, or polycarpy.C. solstitialis had been reported to be diploid (2n = 2x = 16 chromosomes), however, actual data are scarce and sometimes contradictory.Methods.We determined for the first time the absolute nuclear DNA content by flow cytometry and estimated ploidy level in 52 natural populations of C. solstitialis across its native and non-native ranges, around the world.Results.All the C. solstitialis populations screened were found to be homogeneously diploid (average 2C value of 1.72 pg, SD = ± 0.06 pg) with no significant variation in DNA content between invasive and non-invasive genotypes.Discussion.We did not find any meaningful difference among the extensive number of native and non-native C. solstitialis populations sampled around the globe, indicating that the species invasive success is not due to changes in genome size or ploidy level.

Centaurea

10.7287/peerj.3531v0.1/reviews/3

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Citations (0)

The effect of Teach for America on the distribution of student achievement in primary school: Evidence from a randomized experiment

Economics of Education Review (2013)

Heather Antecol Özkan Eren Serkan Ozbeklik

Disadvantaged

Quantile

Student Achievement

Quantile regression

10.1016/j.econedurev.2013.08.004

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Citations (19)

The Effect of Grade Retention on Adult Crime: Evidence from a Test-Based Promotion Policy

RePEc: Research Papers in Economics (2020)

Özkan Eren Michael Lovenheim Naci Mocan

Promotion (chess)

Grade retention

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Citations (0)

Judges, Juveniles, and In-Group Bias

The Journal of Law and Economics (2017)

Briggs Depew Özkan Eren Naci Mocan

We investigate the existence of in-group bias (preferential treatment of one's own group) in court decisions. Using the universe of juvenile-court cases in a US state between 1996 and 2012 and exploiting random assignment of juvenile defendants to judges, we find evidence for negative racial in-group bias in judicial decisions. All else being equal, black (white) juveniles who are randomly assigned to black (white) judges are more likely to be placed in custody, as opposed to being placed on probation, and they receive longer sentences. Although observed in experimental settings, this is the first empirical evidence of negative in-group bias based on a randomization design outside the lab. We provide explanations for this finding.

Random assignment

Racial Bias

White (mutation)

Randomized experiment

10.1086/693822

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Citations (53)

Community Assembly Theory as a Framework for Biological Invasions

Trends in Ecology & Evolution (2018)

Dean E. Pearson Yvette K. Ortega Özkan Eren José L. Hierro

10.1016/j.tree.2018.03.002

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Citations (216)

Are We Wasting Our Children's Time by Giving Them More Homework?

Özkan Eren Daniel J. Henderson

Following an identification strategy that allows us to largely eliminate unobserved student and teacher traits, we examine the effect of homework on math, science, English and history test scores for eighth grade students in the United States. Noting that failure to control for these effects yields selection biases on the estimated effect of homework, we find that math homework has a large and statistically meaningful effect on math test scores throughout our sample. However, additional homework in science, English and history are shown to have little to no impact on their respective test scores.

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Citations (0)

Non‐native conditions favor non‐native populations of invasive plant: demographic consequences of seed size variation?

Oikos (2012)

José L. Hierro Özkan Eren Diego Villarreal Mariana C. Chiuffo

Trait differences between native and non‐native populations may explain the greater abundance and impact of some organisms in their non‐native ranges than in their native ranges. Here, we conducted reciprocal common gardens in southwestern Turkey (home) and central Argentina (away) to explore the hypothesis that the greater success of the invasive ruderal Centaurea solstitialis in Argentina than Turkey is partially explained by differences between home and away populations. Unusual among common gardens, our experimental design included seed additions to explicitly evaluate population level responses, as well as disturbance and no‐disturbance treatments. We documented seed mass in native and non‐native populations, and during the experiment, we periodically measured density, plant size, and herbivory. After six months, we determined the establishment of plants for populations from both origins in both home and away common gardens. Seed mass was two times larger for Argentinean than Turkish populations. Density, plant size and final establishment were also greater for plants from Argentinean than from Turkish populations, but only in the common garden in Argentina. In Turkey, no differences between population origins were detected for these variables. Herbivory was similar for populations from both origins in both common gardens. As expected, disturbance generally increased plant performance in both regions. Our results suggest that increased seed size in non‐native populations may have demographic consequences under non‐native conditions that can contribute to the invasive success of C. solstitialis . This is the first reciprocal common garden that supports the idea that seed size variation contributes to demographic differences for an invasive species between native and non‐native distributions, but our findings further suggest that seed size effects on demography depend on the ecological context in which population processes occur.

Ruderal species

Native plant

Trait

10.1111/j.1600-0706.2012.00022.x

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Citations (43)