Nested LMM (Hiyerarşik Karma Model)
v1.0.1
Social, Human and Administrative Sciences context — fixed effect (treatment) + nested random effects. is_tatmini_skoru ~ tedavi + (1|sektor/firma/calisan). Difference from VARCOMP: a fixed effect (e.g. treatment/group comparison) is added.
🎯 What is it for?
When interpreting fixed effects in hierarchical data, it also accounts for the variance of the random factors. In the Social, Humanities and Administrative Sciences, if the same employees receive different treatments, a classical t-test/ANOVA ignores the clustering → type-I error. Nested LMM computes this correctly.
📌 When is it used?
- Comparison of a fixed effect (treatment, intervention, condition) + hierarchical sampling
- Multi-site clinical research, multi-center field trial
- Adjusting site/group-level variance in RCTs
⚙ Assumptions
- Continuous DV, categorical fixed effect.
- Nested structure: firma within sektor, calisan within firma.
- Random effects ~ Normal(0, σ²).
- ≥1 observation in each treatment-calisan combination.
📊 How to Run It in MerQur
Panel assignments (form fields in the program):
- Dependent Variable:
deger - Replication Variable:
blok - Upper Group:
ust_grup - Inner (Nested) Group:
alt_grup_no - SS Type:
1
🧪 Example Data — Social, Human and Administrative Sciences
📂 samples/Ileri_Duzey_v102/sosyal-beseri-idari/108_nested_lmm.xlsx · n = 216 · Treatment: Control/Treatment-A/Treatment-B · Hierarchy: sector/company/employee
⬇ Download the example data set (.xlsx)
| sektor | firma | calisan | tedavi | is_tatmini_skoru |
|---|---|---|---|---|
| SEKTOR_01 | FIRMA_01_01 | CALISAN_01_01_01 | Kontrol | 2.3 |
| SEKTOR_01 | FIRMA_01_01 | CALISAN_01_01_01 | Tedavi-A | 5.857 |
| SEKTOR_01 | FIRMA_01_01 | CALISAN_01_01_01 | Tedavi-B | 9.309 |
| SEKTOR_01 | FIRMA_01_01 | CALISAN_01_01_02 | Kontrol | 3.107 |
| SEKTOR_01 | FIRMA_01_01 | CALISAN_01_01_02 | Tedavi-A | 6.265 |
| … | … | … | … | … |
📊 MerQur Output (summary)
==================================================
Fixed effect (tedavi) β̂ SE p
Kontrol (ref) 0.00 – –
Tedavi-A +4.0 1.20 < .001 Tedavi-B +7.0 1.20 < .001 Random components σ² sektor 0.16 firma 0.09 calisan 0.09 Residual 0.16
📄 APA 7 Yorumu
⚠ Common Mistakes
- Specifying “crossed” instead of “nested” — the firma-id values must not repeat across each sektor.
- Optimizer failure (lbfgs llf=inf) — MerQur resolves this with a bfgs/cg cascade.
- Treatment × sektor imbalance — the fixed-effect coefficient may be biased.
📚 Cite MerQur
Örücü, Ö. K. (2026). MerQur: An Integrated Platform for Academic Data Analysis and Reporting [Computer Software] (Version 1.0.0). https://doi.org/10.53463/merqur.2026001
📝 Production Note — The sample data on this page was generated synthetically (fixed SEED=42, generator: samples/Ileri_Duzey_v102/_generate_v102_datasets.py). The page content was prepared with the support of Anthropic Claude, and its academic accuracy was verified by the author.