diff --git a/EpiAware/docs/src/developer/contributing.md b/EpiAware/docs/src/developer/contributing.md
index 67520dfe9..0ad416c8f 100644
--- a/EpiAware/docs/src/developer/contributing.md
+++ b/EpiAware/docs/src/developer/contributing.md
@@ -40,6 +40,22 @@ Tests that build example package docs from source and inspect the results (end t
 located in `/test/examples`. The main entry points are `test/examples/make.jl` for building and
 `test/examples/test.jl` for doing some basic checks on the generated outputs.
 
+## Benchmarking
+
+Benchmarking is orchestrated using `PkgBenchmark.jl` along with a GitHub action that uses `BenchmarkCI.jl` The benchmarks are located in `benchmarks/` and the main entry point is `benchmarks/runbenchmarks.jl`.
+
+The main function in the `benchmark` environment is `make_epiaware_suite` which calls `TuringBenchmarking.make_turing_suite` on a set of `Turing` models generated by `EpiAware` benchmarking their sampling with the following autodiff backends:
+
+- `ForwardDiff.jl`.
+- `ReverseDiff.jl`: With `compile = false`.
+- `ReverseDiff.jl`: With `compile = true`.
+
+### Benchmarking "gotchas"
+
+#### Models with no parameters
+
+In `EpiAware` we do expose some models thats do not have parameters, for example, Poisson sampling with a transformation on a fixed mean process implemented by `TransformObservationModel(NegativeBinomialError())` has no sampleable parameters (although it does contributed log-likelihood as part of a wider model). This causes `TuringBenchmarking.make_turing_suite` to throw an error as it expects all models to have parameters.
+
 ## Pluto usage in showcase documentation
 
 Some of the showcase examples in `EpiAware/docs/src/showcase` use [`Pluto.jl`](https://plutojl.org/) notebooks for the underlying computation. The output of the notebooks is rendered into HTML for inclusion in the documentation in two steps:
diff --git a/EpiAware/src/EpiObsModels/EpiObsModels.jl b/EpiAware/src/EpiObsModels/EpiObsModels.jl
index 4f0137fbd..d24a675ea 100644
--- a/EpiAware/src/EpiObsModels/EpiObsModels.jl
+++ b/EpiAware/src/EpiObsModels/EpiObsModels.jl
@@ -11,7 +11,7 @@ using ..EpiLatentModels: HierarchicalNormal, broadcast_dayofweek
 using ..EpiLatentModels: broadcast_rule, PrefixLatentModel, RepeatEach
 
 using Turing, Distributions, DocStringExtensions, SparseArrays, LinearAlgebra
-using LogExpFunctions: xexpy
+using LogExpFunctions: xexpy, log1pexp
 
 # Observation error models
 export PoissonError, NegativeBinomialError
@@ -21,7 +21,7 @@ export generate_observation_error_priors, observation_error
 
 # Observation model modifiers
 export LatentDelay, Ascertainment, PrefixObservationModel, RecordExpectedObs
-export Aggregate
+export Aggregate, TransformObservationModel
 
 # Observation model manipulators
 export StackObservationModels
@@ -36,6 +36,7 @@ include("modifiers/ascertainment/helpers.jl")
 include("modifiers/Aggregate.jl")
 include("modifiers/PrefixObservationModel.jl")
 include("modifiers/RecordExpectedObs.jl")
+include("modifiers/TransformObservationModel.jl")
 include("StackObservationModels.jl")
 include("ObservationErrorModels/methods.jl")
 include("ObservationErrorModels/NegativeBinomialError.jl")
diff --git a/EpiAware/src/EpiObsModels/modifiers/TransformObservationModel.jl b/EpiAware/src/EpiObsModels/modifiers/TransformObservationModel.jl
new file mode 100644
index 000000000..cda094f26
--- /dev/null
+++ b/EpiAware/src/EpiObsModels/modifiers/TransformObservationModel.jl
@@ -0,0 +1,56 @@
+@doc raw"
+The `TransformObservationModel` struct represents an observation model that applies a transformation function to the expected observations before passing them to the underlying observation model.
+
+## Fields
+- `model::M`: The underlying observation model.
+- `transform::F`: The transformation function applied to the expected observations.
+
+## Constructors
+- `TransformObservationModel(model::M, transform::F = x -> log1pexp.(x)) where {M <: AbstractTuringObservationModel, F <: Function}`: Constructs a `TransformObservationModel` instance with the specified observation model and a default transformation function.
+- `TransformObservationModel(; model::M, transform::F = x -> log1pexp.(x)) where {M <: AbstractTuringObservationModel, F <: Function}`: Constructs a `TransformObservationModel` instance using named arguments.
+- `TransformObservationModel(model::M; transform::F = x -> log1pexp.(x)) where {M <: AbstractTuringObservationModel, F <: Function}`: Constructs a `TransformObservationModel` instance with the specified observation model and a default transformation function.
+
+## Example
+
+```julia
+using EpiAware, Distributions, LogExpFunctions
+
+trans_obs = TransformObservationModel(NegativeBinomialError())
+gen_obs = generate_observations(trans_obs, missing, fill(10.0, 30))
+gen_obs()
+```
+"
+@kwdef struct TransformObservationModel{
+    M <: AbstractTuringObservationModel, F <: Function} <: AbstractTuringObservationModel
+    "The underlying observation model."
+    model::M
+    "The transformation function. The default is `log1pexp` which is the softplus transformation"
+    transform::F = x -> log1pexp.(x)
+end
+
+function TransformObservationModel(model::M;
+        transform::F = x -> log1pexp.(x)) where {
+        M <: AbstractTuringObservationModel, F <: Function}
+    return TransformObservationModel(model, transform)
+end
+
+@doc raw"
+Generates observations or accumulates log-likelihood based on the `TransformObservationModel`.
+
+## Arguments
+- `obs::TransformObservationModel`: The TransformObservationModel.
+- `y_t`: The current state of the observations.
+- `Y_t`: The expected observations.
+
+## Returns
+- `y_t`: The updated observations.
+"
+@model function EpiAwareBase.generate_observations(
+        obs::TransformObservationModel, y_t, Y_t
+)
+    transformed_Y_t = obs.transform(Y_t)
+
+    @submodel y_t = generate_observations(obs.model, y_t, transformed_Y_t)
+
+    return y_t
+end
diff --git a/EpiAware/test/EpiLatentModels/models/RandomWalk.jl b/EpiAware/test/EpiLatentModels/models/RandomWalk.jl
index ef562dbbf..d2efa4a3b 100644
--- a/EpiAware/test/EpiLatentModels/models/RandomWalk.jl
+++ b/EpiAware/test/EpiLatentModels/models/RandomWalk.jl
@@ -44,23 +44,23 @@ end
           ReverseDiff
     Random.seed!(1234)
 
-    rw_process = RandomWalk()
-    obs_nb = NegativeBinomialError()
+    process = RandomWalk()
+    obs = PoissonError()
 
-    @model function test_negbin_errors(rw, obs, y_t)
+    @model function test_poisson_errors(proc, obs, y_t)
         n = length(y_t)
-        @submodel Z_t = generate_latent(rw, n)
+        @submodel Z_t = generate_latent(proc, n)
         @submodel y_t = generate_observations(obs, y_t, exp.(Z_t))
         return Z_t, y_t
     end
 
-    generative_mdl = test_negbin_errors(rw_process, obs_nb, fill(missing, 40))
+    generative_mdl = test_poisson_errors(process, obs, fill(missing, 40))
     θ_true = rand(generative_mdl)
     Z_t_obs, y_t_obs = condition(generative_mdl, θ_true)()
 
-    mdl = test_negbin_errors(rw_process, obs_nb, Int.(y_t_obs))
+    mdl = test_poisson_errors(process, obs, Int.(y_t_obs))
     chn = sample(
-        mdl, NUTS(adtype = AutoReverseDiff(; compile = Val(true))), 1000, progess = false)
+        mdl, NUTS(adtype = AutoReverseDiff(; compile = Val(true))), 1000; progess = false)
 
     #Check that are in central 99.9% of the posterior predictive distribution
     #Therefore, this should be unlikely to fail if the model is correctly implemented
diff --git a/EpiAware/test/EpiObsModels/modifiers/LatentDelay.jl b/EpiAware/test/EpiObsModels/modifiers/LatentDelay.jl
index 2b4b52102..f1bddcb22 100644
--- a/EpiAware/test/EpiObsModels/modifiers/LatentDelay.jl
+++ b/EpiAware/test/EpiObsModels/modifiers/LatentDelay.jl
@@ -162,7 +162,7 @@ end
     end
 end
 
-@testitem "LatentDelay parameter recovery with mix of IGP + latent processes: Negative binomial errors + EpiProblem interface" begin
+@testitem "LatentDelay parameter recovery with mix of IGP + latent processes: Poisson errors + EpiProblem interface" begin
     using Random, Turing, Distributions, LinearAlgebra, DynamicPPL, StatsBase, ReverseDiff,
           Suppressor, LogExpFunctions
     # using PairPlots, CairoMakie
@@ -178,7 +178,7 @@ end
         data = EpiData([0.2, 0.5, 0.3],
             em_type == Renewal ? softplus : exp
         ),
-        initialisation_prior = Normal(log(100.0), 0.25)
+        initialisation_prior = Normal(log(100.0), 0.01)
     )
 
     latentprocess_types = [RandomWalk, AR, DiffLatentModel]
@@ -190,7 +190,7 @@ end
             return (; init_prior, std_prior)
         elseif epimodel isa ExpGrowthRate
             init_prior = Normal(0.1, 0.025)
-            std_prior = HalfNormal(0.025)
+            std_prior = LogNormal(log(0.025), 0.01)
             return (; init_prior, std_prior)
         elseif epimodel isa DirectInfections
             init_prior = Normal(log(100.0), 0.25)
@@ -204,11 +204,11 @@ end
         if latentprocess_type == RandomWalk
             return RandomWalk(init_prior, std_prior)
         elseif latentprocess_type == AR
-            return AR(damp_priors = [Beta(8, 2; check_args = false)],
+            return AR(damp_priors = [Beta(2, 8; check_args = false)],
                 std_prior = std_prior, init_priors = [init_prior])
         elseif latentprocess_type == DiffLatentModel
             return DiffLatentModel(
-                AR(damp_priors = [Beta(8, 2; check_args = false)],
+                AR(damp_priors = [Beta(2, 8; check_args = false)],
                     std_prior = std_prior, init_priors = [Normal(0.0, 0.25)]),
                 init_prior; d = 1)
         end
@@ -217,15 +217,14 @@ end
     function test_full_process(epimodel, latentprocess, n;
             ad = AutoReverseDiff(; compile = true), posterior_p_tol = 0.005)
         #Fix observation model
-        obs = LatentDelay(
-            NegativeBinomialError(cluster_factor_prior = HalfNormal(0.05)), Gamma(3, 7 / 3))
+        obs = LatentDelay(PoissonError(), Gamma(3, 7 / 3))
 
         #Inference method
         inference_method = EpiMethod(
-            pre_sampler_steps = [ManyPathfinder(nruns = 4, maxiters = 100)],
+            pre_sampler_steps = [ManyPathfinder(nruns = 4, maxiters = 50)],
             sampler = NUTSampler(adtype = ad,
-                ndraws = 1000,
-                nchains = 4,
+                ndraws = 2000,
+                nchains = 2,
                 mcmc_parallel = MCMCThreads())
         )
 
@@ -237,15 +236,15 @@ end
         )
 
         #Generate data from generative model (i.e. data unconditioned)
-        generative_mdl = generate_epiaware(
-            epi_prob, (y_t = Vector{Union{Int, Missing}}(missing, n),))
+        generative_mdl = generate_epiaware(epi_prob, (y_t = missing,))
         θ_true = rand(generative_mdl)
         gen_data = condition(generative_mdl, θ_true)()
 
         #Apply inference method to inference model (i.e. generative model conditioned on data)
         inference_results = apply_method(epi_prob,
             inference_method,
-            (y_t = gen_data.generated_y_t,)
+            (y_t = gen_data.generated_y_t,);
+            progress = false
         )
 
         chn = inference_results.samples
@@ -265,7 +264,7 @@ end
     @testset "Check true parameters are within 99% central post. prob.: " begin
         @testset for latentprocess_type in latentprocess_types, epimodel in epimodels
             latentprocess = set_latent_process(epimodel, latentprocess_type)
-            @suppress _ = test_full_process(epimodel, latentprocess, 50)
+            @suppress _ = test_full_process(epimodel, latentprocess, 40)
         end
     end
 end
diff --git a/EpiAware/test/EpiObsModels/modifiers/TransformObservationModel.jl b/EpiAware/test/EpiObsModels/modifiers/TransformObservationModel.jl
new file mode 100644
index 000000000..2b4fa4a91
--- /dev/null
+++ b/EpiAware/test/EpiObsModels/modifiers/TransformObservationModel.jl
@@ -0,0 +1,48 @@
+@testitem "Test TransformObservationModel constructor" begin
+    using Turing, LogExpFunctions
+
+    # Test default constructor
+    trans_obs = TransformObservationModel(NegativeBinomialError())
+    @test trans_obs.model == NegativeBinomialError()
+    @test trans_obs.transform([1.0, 2.0, 3.0]) == log1pexp.([1.0, 2.0, 3.0])
+
+    # Test constructor with custom transform
+    custom_transform = x -> exp.(x)
+    trans_obs_custom = TransformObservationModel(NegativeBinomialError(), custom_transform)
+    @test trans_obs_custom.model == NegativeBinomialError()
+    @test trans_obs_custom.transform([1.0, 2.0, 3.0]) == exp.([1.0, 2.0, 3.0])
+
+    # Test kwarg constructor
+    trans_obs_kwarg = TransformObservationModel(
+        model = PoissonError(), transform = custom_transform)
+    @test trans_obs_kwarg.model == PoissonError()
+    @test trans_obs_kwarg.transform == custom_transform
+end
+
+@testitem "Test TransformObservationModel generate_observations" begin
+    using Turing, LogExpFunctions, Distributions
+
+    # Test with default log1pexp transform
+    trans_obs = TransformObservationModel(NegativeBinomialError())
+    gen_obs = generate_observations(trans_obs, missing, fill(10.0, 1))
+    samples = sample(gen_obs, Prior(), 1000; progress = false)["y_t[1]"]
+
+    # Reverse the transform
+    reversed_samples = samples .|> exp |> x -> x .- 1 .|> log
+    # Apply the transform again
+    recovered_samples = log1pexp.(reversed_samples)
+
+    @test all(isapprox.(samples, recovered_samples, rtol = 1e-6))
+
+    # Test with custom transform and Poisson distribution
+    custom_transform = x -> x .^ 2  # Square transform
+    trans_obs_custom = TransformObservationModel(PoissonError(), custom_transform)
+    gen_obs_custom = generate_observations(trans_obs_custom, missing, fill(5.0, 1))
+    samples_custom = sample(gen_obs_custom, Prior(), 1000; progress = false)
+    # Reverse the transform
+    reversed_samples_custom = sqrt.(samples_custom["y_t[1]"])
+    # Apply the transform again
+    recovered_samples_custom = custom_transform.(reversed_samples_custom)
+
+    @test all(isapprox.(samples_custom["y_t[1]"], recovered_samples_custom, rtol = 1e-6))
+end
diff --git a/benchmark/bench/EpiObsModels/EpiObsModels.jl b/benchmark/bench/EpiObsModels/EpiObsModels.jl
index 2b2a76000..73d8f180e 100644
--- a/benchmark/bench/EpiObsModels/EpiObsModels.jl
+++ b/benchmark/bench/EpiObsModels/EpiObsModels.jl
@@ -8,6 +8,8 @@ include("modifiers/ascertainment/Ascertainment.jl")
 include("modifiers/ascertainment/helpers.jl")
 include("modifiers/LatentDelay.jl")
 include("modifiers/PrefixObservationModel.jl")
+include("modifiers/RecordExpectedObs.jl")
+include("modifiers/TransformObservationModel.jl")
 include("ObservationErrorModels/methods.jl")
 include("ObservationErrorModels/NegativeBinomialError.jl")
 include("ObservationErrorModels/PoissonError.jl")
diff --git a/benchmark/bench/EpiObsModels/modifiers/TransformObservationModel.jl b/benchmark/bench/EpiObsModels/modifiers/TransformObservationModel.jl
new file mode 100644
index 000000000..8c46191ae
--- /dev/null
+++ b/benchmark/bench/EpiObsModels/modifiers/TransformObservationModel.jl
@@ -0,0 +1,5 @@
+let
+    transform_obs = TransformObservationModel(NegativeBinomialError())
+    mdl = generate_observations(transform_obs, fill(10, 10), fill(9, 10))
+    suite["TransformObservationModel"] = make_epiaware_suite(mdl)
+end